[ViewVC] Diff of: cvs/gvpe/doc/gvpe.texi

Comparing gvpe/doc/gvpe.texi (file contents):
Revision 1.4 by pcg, Mon Sep 1 05:31:28 2008 UTC vs.
Revision 1.5 by root, Tue Feb 15 13:31:22 2011 UTC

…		…
33		33
34	@end ifinfo	34	@end ifinfo
35		35
36	@titlepage	36	@titlepage
37	@title gvpe Manual	37	@title gvpe Manual
38	@author Marc Lehmann	38	@author Marc Lehmann
39		39
40	@page	40	@page
41	@vskip 0pt plus 1filll	41	@vskip 0pt plus 1filll
42	@cindex copyright	42	@cindex copyright
43		43
…		…
98		98
99	@itemize	99	@itemize
100		100
101		101
102	@item	102	@item
103
104	@cindex Virtual
105	Virtual	103	Virtual
106		104
107	Virtual means that no physical network is created (of course), but a network is @emph{emulated} by creating multiple tunnels between the member nodes by encapsulating and sending data over another transport network.	105	Virtual means that no physical network is created (of course), but a network is @emph{emulated} by creating multiple tunnels between the member nodes by encapsulating and sending data over another transport network.
108	@refill	106	@refill
109	Usually the emulated network is a normal IP or Ethernet, and the transport network is the Internet. However, using a VPN system like GVPE to connect nodes over other untrusted networks such as Wireless LAN is not uncommon.	107	Usually the emulated network is a normal IP or Ethernet, and the transport network is the Internet. However, using a VPN system like GVPE to connect nodes over other untrusted networks such as Wireless LAN is not uncommon.
110	@refill	108	@refill
111		109
112		110
113	@item	111	@item
114
115	@cindex Private
116	Private	112	Private
117		113
118	Private means that non-participating nodes cannot decode ("sniff)" nor inject ("spoof") packets. This means that nodes can be connected over untrusted networks such as the public Internet without fear of being eavesdropped while at the same time being able to trust data sent by other nodes.	114	Private means that non-participating nodes cannot decode ("sniff)" nor inject ("spoof") packets. This means that nodes can be connected over untrusted networks such as the public Internet without fear of being eavesdropped while at the same time being able to trust data sent by other nodes.
119	@refill	115	@refill
120	In the case of GVPE, even participating nodes cannot sniff packets send to other nodes or spoof packets as if sent from other nodes, so communications between any two nodes is private to those two nodes.	116	In the case of GVPE, even participating nodes cannot sniff packets send to other nodes or spoof packets as if sent from other nodes, so communications between any two nodes is private to those two nodes.
121	@refill	117	@refill
122		118
123		119
124	@item	120	@item
125
126	@cindex Network
127	Network	121	Network
128		122
129	Network means that more than two parties can participate in the network, so for instance it's possible to connect multiple branches of a company into a single network. Many so-called "vpn" solutions only create point-to-point tunnels, which in turn can be used to build larger networks.	123	Network means that more than two parties can participate in the network, so for instance it's possible to connect multiple branches of a company into a single network. Many so-called "VPN" solutions only create point-to-point tunnels, which in turn can be used to build larger networks.
130	@refill	124	@refill
131	GVPE provides a true multi-point network in wich any number of nodes (at least a few dozen in practise, the theoretical limit is 4095 nodes) can participate.	125	GVPE provides a true multi-point network in which any number of nodes (at least a few dozen in practise, the theoretical limit is 4095 nodes) can participate.
132	@refill	126	@refill
133	@end itemize	127	@end itemize
134		128
135		129
136		130
…		…
162	@end itemize	156	@end itemize
163		157
164		158
165		159
166	@section PROGRAMS	160	@section PROGRAMS
167	Vpe comes with two programs: one daemon (@t{gvpe}) and one control program (@t{gvpectrl}).	161	Gvpe comes with two programs: one daemon (@t{gvpe}) and one control program (@t{gvpectrl}).
168	@refill	162	@refill
169		163
170		164
171	@itemize	165	@itemize
172		166
173		167
174	@item	168	@item
175	gvpectrl	169	gvpectrl
176		170
177	Is used to generate the keys, check and give an overview of of the configuration and contorl the daemon (restarting etc.).	171	This program is used to generate the keys, check and give an overview of of the configuration and to control the daemon (restarting etc.).
178	@refill	172	@refill
179		173
180		174
181	@item	175	@item
182	gvpe	176	gvpe
183		177
184	Is the daemon used to establish and maintain connections to the other network members. It should be run on the gateway machine.	178	This is the daemon used to establish and maintain connections to the other network nodes. It should be run on the gateway of each VPN subnet.
185	@refill	179	@refill
186	@end itemize	180	@end itemize
187		181
188		182
189		183
190	@section COMPILETIME CONFIGURATION	184	@section COMPILETIME CONFIGURATION
191	Please have a look at the @t{gvpe.osdep(5)} manpage for platform-specific information.	185	Please have a look at the @t{gvpe.osdep(5)} manpage for platform-specific information.
192	@refill	186	@refill
		187	Gvpe hardcodes most encryption parameters. While this reduces flexibility, it makes the program much simpler and helps making buffer overflows impossible under most circumstances.
		188	@refill
193	Here are a few recipes for compiling your gvpe, showing the extremes (fast, small, insecure OR slow, large, more secure), between you should choose:	189	Here are a few recipes for compiling your gvpe, showing the extremes (fast, small, insecure OR slow, large, more secure), between which you should choose:
194	@refill	190	@refill
195		191
196		192
197	@subsection AS LOW PACKET OVERHEAD AS POSSIBLE	193	@subsection AS LOW PACKET OVERHEAD AS POSSIBLE
198		194
199		195
200	@example	196	@example
201	./configure --enable-hmac-length=4 --enable-rand-length=0	197	./configure --enable-hmac-length=4 --enable-rand-length=0
202	@end example	198	@end example
203		199
204	Minimize the header overhead of VPN packets (the above will result in only 4 bytes of overhead over the raw ethernet frame). This is a insecure configuration because a HMAC length of 4 makes collision attacks based on the birthday paradox easy, though.	200	Minimize the header overhead of VPN packets (the above will result in only 4 bytes of overhead over the raw ethernet frame). This is a insecure configuration because a HMAC length of 4 makes collision attacks based on the birthday paradox pretty easy.
205	@refill	201	@refill
206		202
207		203
208	@subsection MINIMIZE CPU TIME REQUIRED	204	@subsection MINIMIZE CPU TIME REQUIRED
209		205
210		206
211	@example	207	@example
212	./configure --enable-cipher=bf --enable-digest=md4	208	./configure --enable-cipher=bf --enable-digest=md4
213	@end example	209	@end example
214		210
215	Use the fastest cipher and digest algorithms currently available in gvpe. MD4 has been broken and is quite insecure, though.	211	Use the fastest cipher and digest algorithms currently available in gvpe. MD4 has been broken and is quite insecure, though, so using another digest algorithm is recommended.
216	@refill	212	@refill
217		213
218		214
219	@subsection MAXIMIZE SECURITY	215	@subsection MAXIMIZE SECURITY
220		216
221		217
222	@example	218	@example
223	./configure --enable-hmac-length=16 --enable-rand-length=8 --enable-digest=sha1	219	./configure --enable-hmac-length=16 --enable-rand-length=8 --enable-digest=sha1
224	@end example	220	@end example
225		221
226	This uses a 16 byte HMAC checksum to authenticate packets (I guess 8-12 would also be pretty secure ;) and will additionally prefix each packet with 8 bytes of random data. In the long run, people should move to SHA-224 and beyond, but support in openssl is missing as of writing this document.	222	This uses a 16 byte HMAC checksum to authenticate packets (I guess 8-12 would also be pretty secure ;) and will additionally prefix each packet with 8 bytes of random data. In the long run, people should move to SHA-256 and beyond).
227	@refill	223	@refill
228	In general, remember that AES-128 seems to be more secure and faster than AES-192 or AES-256, more randomness helps against sniffing and a longer HMAC helps against spoofing. MD4 is a fast digest, SHA1 or RIPEMD160 are better, and Blowfish is a fast cipher (and also quite secure).	224	In general, remember that AES-128 seems to be as secure but faster than AES-192 or AES-256, more randomness helps against sniffing and a longer HMAC helps against spoofing. MD4 is a fast digest, SHA1, RIPEMD160, SHA256 are consecutively better, and Blowfish is a fast cipher (and also quite secure).
229	@refill	225	@refill
230		226
231		227
232	@section HOW TO SET UP A SIMPLE VPN	228	@section HOW TO SET UP A SIMPLE VPN
233	In this section I will describe how to get a simple VPN consisting of three hosts up and running.	229	In this section I will describe how to get a simple VPN consisting of three hosts up and running.
234	@refill	230	@refill
235		231
236		232
237	@subsection STEP 1: configuration	233	@subsection STEP 1: configuration
238	First you have to create a daemon configuation file and put it into the configuration directory. This is usually @t{/etc/gvpe}, depending on how you configured gvpe, and can be overwritten using the @t{-c} commandline switch.	234	First you have to create a daemon configuration file and put it into the configuration directory. This is usually @t{/etc/gvpe}, depending on how you configured gvpe, and can be overwritten using the @t{-c} command line switch.
239	@refill	235	@refill
240	Put the following lines into @t{/etc/gvpe/gvpe.conf}:	236	Put the following lines into @t{/etc/gvpe/gvpe.conf}:
241	@refill	237	@refill
242		238
243		239
244	@example	240	@example
245	udp-port = 50000 # the external port to listen on (configure your firewall)	241	udp-port = 50000 # the external port to listen on (configure your firewall)
246	mtu = 1400 # minimum MTU of all outgoing interfaces on all hosts	242	mtu = 1400 # minimum MTU of all outgoing interfaces on all hosts
247	ifname = vpn0 # the local network device name	243	ifname = vpn0 # the local network device name
248	@end example
249		244
250
251
252	@example
253	node = first # just a nickname	245	node = first # just a nickname
254	hostname = first.example.net # the DNS name or IP address of the host	246	hostname = first.example.net # the DNS name or IP address of the host
255	@end example
256		247
257
258
259	@example
260	node = second	248	node = second
261	hostname = 133.55.82.9	249	hostname = 133.55.82.9
262	@end example
263		250
264
265
266	@example
267	node = third	251	node = third
268	hostname = third.example.net	252	hostname = third.example.net
269	@end example	253	@end example
270		254
271	The only other file neccessary if the @t{if-up} script that initializes the local ethernet interface. Put the following lines into @t{/etc/gvpe/if-up} and make it execute (@t{chmod 755 /etc/gvpe/if-up}):	255	The only other file necessary is the @t{if-up} script that initializes the virtual ethernet interface on the local host. Put the following lines into @t{/etc/gvpe/if-up} and make it executable (@t{chmod 755 /etc/gvpe/if-up}):
272	@refill	256	@refill
273		257
274		258
275	@example	259	@example
276	#!/bin/sh	260	#!/bin/sh
…		…
279	[ $NODENAME = second ] && ip addr add 10.0.2.1 dev $IFNAME	263	[ $NODENAME = second ] && ip addr add 10.0.2.1 dev $IFNAME
280	[ $NODENAME = third ] && ip addr add 10.0.3.1 dev $IFNAME	264	[ $NODENAME = third ] && ip addr add 10.0.3.1 dev $IFNAME
281	ip route add 10.0.0.0/16 dev $IFNAME	265	ip route add 10.0.0.0/16 dev $IFNAME
282	@end example	266	@end example
283		267
284	This script will give each node a different IP address in the @t{10.0/16} network. The internal network (e.g. the @t{eth0} interface) should then be set to a subset of that network, e.g. @t{10.0.1.0/24} on node @t{first}, @t{10.0.2.0/24} on node @t{second}, and so on.	268	This script will give each node a different IP address in the @t{10.0/16} network. The internal network (if gvpe runs on a router) should then be set to a subset of that network, e.g. @t{10.0.1.0/24} on node @t{first}, @t{10.0.2.0/24} on node @t{second}, and so on.
285	@refill	269	@refill
286	By enabling routing on the gateway host that runs @t{gvpe} all nodes will be able to reach the other nodes. You can, of course, also use proxy arp or other means of pseudo-bridging (or even real briding), or (best) full routing - the choice is yours.	270	By enabling routing on the gateway host that runs @t{gvpe} all nodes will be able to reach the other nodes. You can, of course, also use proxy ARP or other means of pseudo-bridging, or (best) full routing - the choice is yours.
287	@refill	271	@refill
288		272
289		273
290	@subsection STEP 2: create the RSA key pairs for all hosts	274	@subsection STEP 2: create the RSA key pairs for all hosts
291	Run the following command to generate all key pairs (that might take a while):	275	Run the following command to generate all key pairs for all nodes (that might take a while):
292	@refill	276	@refill
293		277
294		278
295	@example	279	@example
296	gvpectrl -c /etc/gvpe -g	280	gvpectrl -c /etc/gvpe -g
…		…
299	This command will put the public keys into @t{/etc/gvpe/pubkeys/@emph{nodename}} and the private keys into @t{/etc/gvpe/hostkeys/@emph{nodename}}.	283	This command will put the public keys into @t{/etc/gvpe/pubkeys/@emph{nodename}} and the private keys into @t{/etc/gvpe/hostkeys/@emph{nodename}}.
300	@refill	284	@refill
301		285
302		286
303	@subsection STEP 3: distribute the config files to all nodes	287	@subsection STEP 3: distribute the config files to all nodes
304	Now distribute the config files to the other nodes. This should be done in two steps, since the private keys should not be distributed. The example uses rsync-over-ssh	288	Now distribute the config files and private keys to the other nodes. This should be done in two steps, since only the private keys meant for a node should be distributed (so each node has only it's own private key).
		289	@refill
		290	The example uses rsync-over-ssh
305	@refill	291	@refill
306	First all the config files without the hostkeys should be distributed:	292	First all the config files without the hostkeys should be distributed:
307	@refill	293	@refill
308		294
309		295
…		…
321	rsync -avzessh /etc/gvpe/hostkeys/first first.example.net:/etc/hostkey	307	rsync -avzessh /etc/gvpe/hostkeys/first first.example.net:/etc/hostkey
322	rsync -avzessh /etc/gvpe/hostkeys/second 133.55.82.9:/etc/hostkey	308	rsync -avzessh /etc/gvpe/hostkeys/second 133.55.82.9:/etc/hostkey
323	rsync -avzessh /etc/gvpe/hostkeys/third third.example.net:/etc/hostkey	309	rsync -avzessh /etc/gvpe/hostkeys/third third.example.net:/etc/hostkey
324	@end example	310	@end example
325		311
326	You should now check the configration by issuing the command @t{gvpectrl -c /etc/gvpe -s} on each node and verify it's output.	312	You should now check the configuration by issuing the command @t{gvpectrl -c /etc/gvpe -s} on each node and verify it's output.
327	@refill	313	@refill
328		314
329		315
330	@subsection STEP 4: starting gvpe	316	@subsection STEP 4: starting gvpe
331	You should then start gvpe on each node by issuing a command like:	317	You should then start gvpe on each node by issuing a command like:
332	@refill	318	@refill
333		319
334		320
335	@example	321	@example
336	gvpe -D -linfo first # first is the nodename	322	gvpe -D -l info first # first is the nodename
337	@end example	323	@end example
338		324
339	This will make the gvpe stay in foreground. You should then see "connection established" messages. If you don't see them check your firewall and routing (use tcpdump ;).	325	This will make the gvpe daemon stay in foreground. You should then see "connection established" messages. If you don't see them check your firewall and routing (use tcpdump ;).
340	@refill	326	@refill
341	If this works you should check your networking setup by pinging various endpoints.	327	If this works you should check your networking setup by pinging various endpoints.
342	@refill	328	@refill
343	To make gvpe run more permanently you can either run it as a daemon (by starting it without the @t{-D} switch), or, much better, from your inittab. I use a line like this on my systems:	329	To make gvpe run more permanently you can either run it as a daemon (by starting it without the @t{-D} switch), or, much better, from your inittab or equivalent. I use a line like this on all my systems:
344	@refill	330	@refill
345		331
346		332
347	@example	333	@example
348	t1:2345:respawn:/opt/gvpe/sbin/gvpe -D -L first >/dev/null 2>&1	334	t1:2345:respawn:/opt/gvpe/sbin/gvpe -D -L first >/dev/null 2>&1
…		…
376	This file tries to capture OS-dependent configuration or build issues, quirks and platform limitations, as known.	362	This file tries to capture OS-dependent configuration or build issues, quirks and platform limitations, as known.
377	@refill	363	@refill
378		364
379		365
380	@section TUN vs. TAP interface	366	@section TUN vs. TAP interface
381	Most operating systems nowadays support something called a @emph{tunnel}-device, which makes it possible to divert IPv4 (and often other protocols, too) into a userspace daemon like @t{gvpe}. This is being referred to as a TUN-device.	367	Most operating systems nowadays support something called a @emph{tunnel}-device, which makes it possible to divert IPv4 (and often other protocols, too) into a user space daemon like @t{gvpe}. This is being referred to as a TUN-device.
382	@refill	368	@refill
383	This is fine for point-to-point tunnels, but for a virtual ethernet, an additional ethernet header is needed. This functionality (called a TAP device here) is only provided by a subset of the configurations.	369	This is fine for point-to-point tunnels, but for a virtual ethernet, an additional ethernet header is needed. This functionality (called a TAP device here) is only provided by a subset of the configurations.
384	@refill	370	@refill
385	On platforms only supporting a TUN-device, gvpe will invoke it's magical ethernet emulation package, which currently only handles ARP requests for the IPv4 protocol (but more could be added, bu the tincd network drivers might need to be modified for this to work). This means that on those platforms, only IPv4 will be supported.	371	On platforms only supporting a TUN-device, gvpe will invoke it's magical ethernet emulation package, which currently only handles ARP requests for the IPv4 protocol (but more could be added, bu the tincd network drivers might need to be modified for this to work). This means that on those platforms, only IPv4 will be supported.
386	@refill	372	@refill
…		…
548		534
549	The interface MAC and MTU are @emph{NOT} set up for you. Please try it out and send me an @t{ifconfig} command invocation that does that.	535	The interface MAC and MTU are @emph{NOT} set up for you. Please try it out and send me an @t{ifconfig} command invocation that does that.
550	@refill	536	@refill
551	See @t{tincd/netbsd} for more information.	537	See @t{tincd/netbsd} for more information.
552	@refill	538	@refill
553	Completely unstested so far.	539	Completely untested so far.
554	@refill	540	@refill
555		541
556		542
557	@subsection tincd/mingw	543	@subsection tincd/mingw
558	TAP-device; see @t{native/cygwin} for more information.	544	TAP-device; see @t{native/cygwin} for more information.
…		…
569	Completely untested so far.	555	Completely untested so far.
570	@refill	556	@refill
571		557
572		558
573	@subsection tincd/uml_socket	559	@subsection tincd/uml_socket
574	TAP-device; purpose unknown and untested, probably creates a unix datagram socket (path given by @t{ifname}) and reads and writes raw packets, so might be useful in other than UML contexts.	560	TAP-device; purpose unknown and untested, probably creates a UNIX datagram socket (path given by @t{ifname}) and reads and writes raw packets, so might be useful in other than UML contexts.
575	@refill	561	@refill
576	No network interface is created, and the MAC and MTU must be set as approriate on the other side of the socket. GVPE will exit if the MAC address doesn't match what it expects.	562	No network interface is created, and the MAC and MTU must be set as appropriate on the other side of the socket. GVPE will exit if the MAC address doesn't match what it expects.
577	@refill	563	@refill
578	Completely untested so far.	564	Completely untested so far.
579	@refill	565	@refill
580		566
581		567
…		…
596		582
597	@section SYNOPSIS	583	@section SYNOPSIS
598		584
599		585
600	@example	586	@example
		587	# global options for all nodes
601	udp-port = 407	588	udp-port = 407
602	mtu = 1492	589	mtu = 1492
603	ifname = vpn0	590	ifname = vpn0
604	@end example
605		591
606		592	# first node is named branch1 and is at 1.2.3.4
607
608	@example
609	node = branch1	593	node = branch1
610	hostname = 1.2.3.4	594	hostname = 1.2.3.4
611	@end example
612		595
613		596	# second node uses dns to resolve the address
614
615	@example
616	node = branch2	597	node = branch2
617	hostname = www.example.net	598	hostname = www.example.net
618	udp-port = 500 # this host uses a different udp-port	599	udp-port = 500 # this host uses a different udp-port
619	@end example
620		600
621		601	# third node has no fixed ip address
622
623	@example
624	node = branch3	602	node = branch3
625	connect = ondemand	603	connect = ondemand
626	@end example	604	@end example
627		605
628		606
…		…
630	@section DESCRIPTION	608	@section DESCRIPTION
631	The gvpe config file consists of a series of lines that contain @t{variable = value} pairs. Empty lines are ignored. Comments start with a @t{#} and extend to the end of the line. They can be used on their own lines, or after any directives. Whitespace is allowed around the @t{=} sign or after values, but not within the variable names or values themselves.	609	The gvpe config file consists of a series of lines that contain @t{variable = value} pairs. Empty lines are ignored. Comments start with a @t{#} and extend to the end of the line. They can be used on their own lines, or after any directives. Whitespace is allowed around the @t{=} sign or after values, but not within the variable names or values themselves.
632	@refill	610	@refill
633	The only exception to the above is the "on" directive that can prefix any @t{name = value} setting and will only "execute" it on the named node, or (if the nodename starts with "!") on all nodes except the named one.	611	The only exception to the above is the "on" directive that can prefix any @t{name = value} setting and will only "execute" it on the named node, or (if the nodename starts with "!") on all nodes except the named one.
634	@refill	612	@refill
		613	For example, set the MTU to @t{1450} everywhere, loglevel to @t{noise} on branch1, and connect to @t{ondemand} everywhere but on branch2:
		614	@refill
635		615
636		616
637	@example	617	@example
638	name = value	618	mtu = 1450
639	on branch1 loglevel = noise	619	on branch1 loglevel = noise
640	on !branch2 connect = ondemand	620	on !branch2 connect = ondemand
641	@end example	621	@end example
642		622
643	All settings are executed "in order", that is, later settings of the same variable overwrite earlier ones.	623	All settings are applied "in order", that is, later settings of the same variable overwrite earlier ones.
644	@refill	624	@refill
645		625
646		626
647	@section ANATOMY OF A CONFIG FILE	627	@section ANATOMY OF A CONFIG FILE
648	Usually, a config file starts with global settings (like the udp port to listen on), followed by node-specific sections that begin with a @t{node = nickname} line.	628	Usually, a config file starts with a few global settings (like the UDP port to listen on), followed by node-specific sections that begin with a @t{node = nickname} line.
649	@refill	629	@refill
650	Every node that is part of the network must have a section that starts with @t{node = nickname}. The number and order of the nodes is important and must be the same on all nodes. It is not uncommon for node sections to be completely empty - if the default values are right.	630	Every node that is part of the network must have a section that starts with @t{node = nickname}. The number and order of the nodes is important and must be the same on all nodes. It is not uncommon for node sections to be completely empty - if the default values are right.
651	@refill	631	@refill
652	Node-specific settings can be used at any time. If used before the first node section they will set the default values for all following nodes.	632	Node-specific settings can be used at any time. If used before the first node section they will set the default values for all following nodes.
653	@refill	633	@refill
…		…
666		646
667	@item	647	@item
668	dns-forw-host = hostname/ip	648	dns-forw-host = hostname/ip
669		649
670	@cindex dns-forw-host	650	@cindex dns-forw-host
671	The dns server to forward dns requests to for the DNS tunnel protocol (default: @t{127.0.0.1}, changing it is highly recommended).	651	The DNS server to forward DNS requests to for the DNS tunnel protocol (default: @t{127.0.0.1}, changing it is highly recommended).
672	@refill	652	@refill
673		653
674		654
675	@item	655	@item
676	dns-forw-port = port-number	656	dns-forw-port = port-number
…		…
684	dns-max-outstanding = integer-number-of-requests	664	dns-max-outstanding = integer-number-of-requests
685		665
686	@cindex dns-max-outstanding	666	@cindex dns-max-outstanding
687	The maximum number of outstanding DNS transport requests (default: @t{100}). GVPE will never issue more requests then the given limit without receiving replies. In heavily overloaded situations it might help to set this to a low number (e.g. @t{3} or even @t{1}) to limit the number of parallel requests.	667	The maximum number of outstanding DNS transport requests (default: @t{100}). GVPE will never issue more requests then the given limit without receiving replies. In heavily overloaded situations it might help to set this to a low number (e.g. @t{3} or even @t{1}) to limit the number of parallel requests.
688	@refill	668	@refill
689	The default should be working ok for most links.	669	The default should be working OK for most links.
690	@refill	670	@refill
691		671
692		672
693	@item	673	@item
694	dns-overlap-factor = float	674	dns-overlap-factor = float
695		675
696	@cindex dns-overlap-factor	676	@cindex dns-overlap-factor
697	The DNS transport uses the minimum request latency (@strong{min_latency}) seen during a connection as it's timing base. This factor (default: @t{0.5}, must be > 0) is multiplied by @strong{min_latency} to get the maximum sending rate (= minimum send interval), i.e. a factor of @t{1} means that a new request might be generated every @strong{min_latency} seconds, which means on average there should only ever be one outstanding request. A factor of @t{0.5} means that GVPE will send requests twice as often as the minimum latency measured.	677	The DNS transport uses the minimum request latency (@strong{min_latency}) seen during a connection as it's timing base. This factor (default: @t{0.5}, must be > 0) is multiplied by @strong{min_latency} to get the maximum sending rate (= minimum send interval), i.e. a factor of @t{1} means that a new request might be generated every @strong{min_latency} seconds, which means on average there should only ever be one outstanding request. A factor of @t{0.5} means that GVPE will send requests twice as often as the minimum latency measured.
698	@refill	678	@refill
699	For congested or picky dns forwarders you could use a value nearer to or exceeding @t{1}.	679	For congested or picky DNS forwarders you could use a value nearer to or exceeding @t{1}.
700	@refill	680	@refill
701	The default should be working ok for most links.	681	The default should be working OK for most links.
702	@refill	682	@refill
703		683
704		684
705	@item	685	@item
706	dns-send-interval = send-interval-in-seconds	686	dns-send-interval = send-interval-in-seconds
707		687
708	@cindex dns-send-interval	688	@cindex dns-send-interval
709	The minimum send interval (= maximum rate) that the DNS transport will use to send new DNS requests. GVPE will not exceed this rate even when the latency is very low. The default is @t{0.01}, which means GVPE will not send more than 100 DNS requests per connection per second. For high-bandwidth links you could go lower, e.g. to @t{0.001} or so. For congested or rate-limited links, you might want to go higher, say @t{0.1}, @t{0.2} or even higher.	689	The minimum send interval (= maximum rate) that the DNS transport will use to send new DNS requests. GVPE will not exceed this rate even when the latency is very low. The default is @t{0.01}, which means GVPE will not send more than 100 DNS requests per connection per second. For high-bandwidth links you could go lower, e.g. to @t{0.001} or so. For congested or rate-limited links, you might want to go higher, say @t{0.1}, @t{0.2} or even higher.
710	@refill	690	@refill
711	The default should be working ok for most links.	691	The default should be working OK for most links.
712	@refill	692	@refill
713		693
714		694
715	@item	695	@item
716	dns-timeout-factor = float	696	dns-timeout-factor = float
…		…
718	@cindex dns-timeout-factor	698	@cindex dns-timeout-factor
719	Factor to multiply the @t{min_latency} (see @t{dns-overlap-factor}) by to get request timeouts. The default of @t{8} means that the DNS transport will resend the request when no reply has been received for longer than eight times the minimum (= expected) latency, assuming the request or reply has been lost.	699	Factor to multiply the @t{min_latency} (see @t{dns-overlap-factor}) by to get request timeouts. The default of @t{8} means that the DNS transport will resend the request when no reply has been received for longer than eight times the minimum (= expected) latency, assuming the request or reply has been lost.
720	@refill	700	@refill
721	For congested links a higher value might be necessary (e.g. @t{30}). If the link is very stable lower values (e.g. @t{2}) might work nicely. Values near or below @t{1} makes no sense whatsoever.	701	For congested links a higher value might be necessary (e.g. @t{30}). If the link is very stable lower values (e.g. @t{2}) might work nicely. Values near or below @t{1} makes no sense whatsoever.
722	@refill	702	@refill
723	The default should be working ok for most links but will result in low throughput if packet loss is high.	703	The default should be working OK for most links but will result in low throughput if packet loss is high.
724	@refill	704	@refill
725		705
726		706
727	@item	707	@item
728	if-up = relative-or-absolute-path	708	if-up = relative-or-absolute-path
729		709
730	@cindex if-up	710	@cindex if-up
731	Sets the path of a script that should be called immediately after the network interface is initialized (but not neccessarily up). The following environment variables are passed to it (the values are just examples).	711	Sets the path of a script that should be called immediately after the network interface is initialized (but not necessarily up). The following environment variables are passed to it (the values are just examples).
732	@refill	712	@refill
733	Variables that have the same value on all nodes:	713	Variables that have the same value on all nodes:
734	@refill	714	@refill
735		715
736		716
…		…
802	MAC=fe:fd:80:00:00:01	782	MAC=fe:fd:80:00:00:01
803		783
804	@cindex MAC	784	@cindex MAC
805	The MAC address the network interface has to use.	785	The MAC address the network interface has to use.
806	@refill	786	@refill
807	Might be used to initialize interfaces on platforms where GVPE does not do this automatically. Please see the @t{gvpe.osdep(5)} manpage for platform-specific information.	787	Might be used to initialize interfaces on platforms where GVPE does not do this automatically. Please see the @t{gvpe.osdep(5)} man page for platform-specific information.
808	@refill	788	@refill
809		789
810		790
811	@item	791	@item
812	NODENAME=branch1	792	NODENAME=branch1
…		…
836	[ $NODENAME = branch1 ] && ip addr add 10.0.0.1 dev $IFNAME	816	[ $NODENAME = branch1 ] && ip addr add 10.0.0.1 dev $IFNAME
837	[ $NODENAME = branch2 ] && ip addr add 10.1.0.1 dev $IFNAME	817	[ $NODENAME = branch2 ] && ip addr add 10.1.0.1 dev $IFNAME
838	ip route add 10.0.0.0/8 dev $IFNAME	818	ip route add 10.0.0.0/8 dev $IFNAME
839	@end example	819	@end example
840		820
841	More complicated examples (using routing to reduce arp traffic) can be found in the etc/ subdirectory of the distribution.	821	More complicated examples (using routing to reduce ARP traffic) can be found in the @file{etc/} subdirectory of the distribution.
842	@refill	822	@refill
843		823
844		824
845	@item	825	@item
846	ifname = devname	826	ifname = devname
…		…
862	ip-proto = numerical-ip-protocol	842	ip-proto = numerical-ip-protocol
863		843
864	@cindex ip-proto	844	@cindex ip-proto
865	Sets the protocol number to be used for the rawip protocol. This is a global option because all nodes must use the same protocol, and since there are no port numbers, you cannot easily run more than one gvpe instance using the same protocol, nor can you share the protocol with other programs.	845	Sets the protocol number to be used for the rawip protocol. This is a global option because all nodes must use the same protocol, and since there are no port numbers, you cannot easily run more than one gvpe instance using the same protocol, nor can you share the protocol with other programs.
866	@refill	846	@refill
867	The default is 47 (GRE), which has a good chance of tunneling through firewalls (but note that the rawip protocol is not GRE compatible). Other common choices are 50 (IPSEC, ESP), 51 (IPSEC, AH), 4 (IPIP tunnels) or 98 (ENCAP, rfc1241)	847	The default is 47 (GRE), which has a good chance of tunneling through firewalls (but note that gvpe's rawip protocol is not GRE compatible). Other common choices are 50 (IPSEC, ESP), 51 (IPSEC, AH), 4 (IPIP tunnels) or 98 (ENCAP, rfc1241).
		848	@refill
		849	Many versions of Linux seem to have a bug that causes them to reorder packets for some ip protocols (GRE, ESP) but not for others (AH), so choose wisely (that is, use 51, AH).
868	@refill	850	@refill
869		851
870		852
871	@item	853	@item
872	http-proxy-host = hostname/ip	854	http-proxy-host = hostname/ip
…		…
874	@cindex http-proxy-host	856	@cindex http-proxy-host
875	The @t{http-proxy-*} family of options are only available if gvpe was compiled with the @t{--enable-http-proxy} option and enable tunneling of tcp connections through a http proxy server.	857	The @t{http-proxy-*} family of options are only available if gvpe was compiled with the @t{--enable-http-proxy} option and enable tunneling of tcp connections through a http proxy server.
876	@refill	858	@refill
877	@t{http-proxy-host} and @t{http-proxy-port} should specify the hostname and port number of the proxy server. See @t{http-proxy-loginpw} if your proxy requires authentication.	859	@t{http-proxy-host} and @t{http-proxy-port} should specify the hostname and port number of the proxy server. See @t{http-proxy-loginpw} if your proxy requires authentication.
878	@refill	860	@refill
879	Please note that gvpe will still try to resolve all hostnames in the configuration file, so if you are behind a proxy without access to a dns server better use numerical IP addresses.	861	Please note that gvpe will still try to resolve all hostnames in the configuration file, so if you are behind a proxy without access to a DNS server better use numerical IP addresses.
880	@refill	862	@refill
881	To make best use of this option disable all protocols except tcp in your config file and make sure your routers (or all other nodes) are listening on a port that the proxy allows (443, https, is a common choice).	863	To make best use of this option disable all protocols except TCP in your config file and make sure your routers (or all other nodes) are listening on a port that the proxy allows (443, https, is a common choice).
882	@refill	864	@refill
883	If you have a router, connecting to it will suffice. Otherwise tcp must be enabled on all nodes.	865	If you have a router, connecting to it will suffice. Otherwise TCP must be enabled on all nodes.
884	@refill	866	@refill
885	Example:	867	Example:
886	@refill	868	@refill
887		869
888		870
…		…
904		886
905	@item	887	@item
906	http-proxy-auth = login:password	888	http-proxy-auth = login:password
907		889
908	@cindex http-proxy-auth	890	@cindex http-proxy-auth
909	The optional login and password used to authenticate to the proxy server, seperated by a literal colon (@t{:}). Only basic authentication is currently supported.	891	The optional login and password used to authenticate to the proxy server, separated by a literal colon (@t{:}). Only basic authentication is currently supported.
910	@refill	892	@refill
911		893
912		894
913	@item	895	@item
914	keepalive = seconds	896	keepalive = seconds
915		897
916	@cindex keepalive	898	@cindex keepalive
917	Sets the keepalive probe interval in seconds (default: @t{60}). After this many seconds of inactivity the daemon will start to send keepalive probe every 5 seconds until it receives a reply from the other end. If no reply is received within 30 seconds, the peer is considered unreachable and the connection is closed.	899	Sets the keepalive probe interval in seconds (default: @t{60}). After this many seconds of inactivity the daemon will start to send keepalive probe every 3 seconds until it receives a reply from the other end. If no reply is received within 15 seconds, the peer is considered unreachable and the connection is closed.
918	@refill	900	@refill
919		901
920		902
921	@item	903	@item
922	loglevel = noise\|trace\|debug\|info\|notice\|warn\|error\|critical	904	loglevel = noise\|trace\|debug\|info\|notice\|warn\|error\|critical
…		…
928		910
929	@item	911	@item
930	mtu = bytes	912	mtu = bytes
931		913
932	@cindex mtu	914	@cindex mtu
933	Sets the maximum MTU that should be used on outgoing packets (basically the MTU of the outgoing interface) The daemon will automatically calculate maximum overhead (e.g. udp header size, encryption blocksize...) and pass this information to the @t{if-up} script.	915	Sets the maximum MTU that should be used on outgoing packets (basically the MTU of the outgoing interface) The daemon will automatically calculate maximum overhead (e.g. UDP header size, encryption blocksize...) and pass this information to the @t{if-up} script.
934	@refill	916	@refill
935	Recommended values are 1500 (ethernet), 1492 (pppoe), 1472 (pptp).	917	Recommended values are 1500 (ethernet), 1492 (pppoe), 1472 (pptp).
936	@refill	918	@refill
937	This value must be the minimum of the mtu values of all nodes.	919	This value must be the minimum of the MTU values of all nodes.
938	@refill	920	@refill
939		921
940		922
941	@item	923	@item
942	node = nickname	924	node = nickname
…		…
950	node-up = relative-or-absolute-path	932	node-up = relative-or-absolute-path
951		933
952	@cindex node-up	934	@cindex node-up
953	Sets a command (default: none) that should be called whenever a connection is established (even on rekeying operations). Note that node-up/down scripts will be run asynchronously, but execution is serialised, so there will only ever be one such script running.	935	Sets a command (default: none) that should be called whenever a connection is established (even on rekeying operations). Note that node-up/down scripts will be run asynchronously, but execution is serialised, so there will only ever be one such script running.
954	@refill	936	@refill
955	In addition to all the variables passed to @t{if-up} scripts, the following environment variables will be set:	937	In addition to all the variables passed to @t{if-up} scripts, the following environment variables will be set (values are just examples):
956	@refill	938	@refill
957		939
958		940
959	@itemize	941	@itemize
960		942
…		…
974	The node id of the remote node.	956	The node id of the remote node.
975	@refill	957	@refill
976		958
977		959
978	@item	960	@item
		961	DESTSI=rawip/88.99.77.55:0
		962
		963	@cindex DESTSI
		964	The "socket info" of the target node, protocol dependent but usually in the format protocol/ip:port.
		965	@refill
		966
		967
		968	@item
979	DESTIP=188.13.66.8	969	DESTIP=188.13.66.8
980		970
981	@cindex DESTIP	971	@cindex DESTIP
982	The numerical IP address of the remote node (gvpe accepts connections from everywhere, as long as the other node can authenticate itself).	972	The numerical IP address of the remote node (gvpe accepts connections from everywhere, as long as the other node can authenticate itself).
983	@refill	973	@refill
…		…
985		975
986	@item	976	@item
987	DESTPORT=655 # deprecated	977	DESTPORT=655 # deprecated
988		978
989	@cindex DESTPORT	979	@cindex DESTPORT
990	The UDP port used by the other side.	980	The protocol port used by the other side, if applicable.
991	@refill	981	@refill
992		982
993		983
994	@item	984	@item
995	STATE=UP	985	STATE=up
996		986
997	@cindex STATE	987	@cindex STATE
998	Node-up scripts get called with STATE=UP, node-down scripts get called with STATE=DOWN.	988	Node-up scripts get called with STATE=up, node-change scripts get called with STATE=change and node-down scripts get called with STATE=down.
999	@refill	989	@refill
1000	@end itemize	990	@end itemize
1001		991
1002	Here is a nontrivial example that uses nsupdate to update the name => ip mapping in some dns zone:	992	Here is a nontrivial example that uses nsupdate to update the name => ip mapping in some DNS zone:
1003	@refill	993	@refill
1004		994
1005		995
1006	@example	996	@example
1007	#!/bin/sh	997	#!/bin/sh
…		…
1013	@end example	1003	@end example
1014		1004
1015		1005
1016		1006
1017	@item	1007	@item
		1008	node-change = relative-or-absolute-path
		1009
		1010	@cindex node-change
		1011	Same as @t{node-change}, but gets called whenever something about a connection changes (such as the source IP address).
		1012	@refill
		1013
		1014
		1015	@item
1018	node-down = relative-or-absolute-path	1016	node-down = relative-or-absolute-path
1019		1017
1020	@cindex node-down	1018	@cindex node-down
1021	Same as @t{node-up}, but gets called whenever a connection is lost.	1019	Same as @t{node-up}, but gets called whenever a connection is lost.
1022	@refill	1020	@refill
…		…
1034	private-key = relative-path-to-key	1032	private-key = relative-path-to-key
1035		1033
1036	@cindex private-key	1034	@cindex private-key
1037	Sets the path (relative to the config directory) to the private key (default: @t{hostkey}). This is a printf format string so every @t{%} must be doubled. A single @t{%s} is replaced by the hostname, so you could use paths like @t{hostkeys/%s} to fetch the files at the location where @t{gvpectrl} puts them.	1035	Sets the path (relative to the config directory) to the private key (default: @t{hostkey}). This is a printf format string so every @t{%} must be doubled. A single @t{%s} is replaced by the hostname, so you could use paths like @t{hostkeys/%s} to fetch the files at the location where @t{gvpectrl} puts them.
1038	@refill	1036	@refill
1039	Since only the private key file of the current node is used and the private key file should be kept secret per-node to avoid spoofings, it is not recommended to use this feature.	1037	Since only the private key file of the current node is used and the private key file should be kept secret per-node to avoid spoofing, it is not recommended to use this feature.
1040	@refill	1038	@refill
1041		1039
1042		1040
1043	@item	1041	@item
1044	rekey = seconds	1042	rekey = seconds
1045		1043
1046	@cindex rekey	1044	@cindex rekey
1047	Sets the rekeying interval in seconds (default: @t{3600}). Connections are reestablished every @t{rekey} seconds.	1045	Sets the rekeying interval in seconds (default: @t{3600}). Connections are reestablished every @t{rekey} seconds, making them use a new encryption key.
1048	@refill	1046	@refill
		1047
		1048
		1049	@item
		1050	nfmark = integer
		1051
		1052	@cindex nfmark
		1053	This advanced option, when set to a nonzero value (default: @t{0}), tries to set the netfilter mark (or fwmark) value on all sockets gvpe uses to send packets.
		1054	@refill
		1055	This can be used to make gvpe use a different set of routing rules. For example, on GNU/Linux, the @t{if-up} could set @t{nfmark} to 1000 and then put all routing rules into table @t{99} and then use an ip rule to make gvpe traffic avoid that routing table, in effect routing normal traffic via gvpe and gvpe traffic via the normal system routing tables:
		1056	@refill
		1057
		1058
		1059	@example
		1060	ip rule add not fwmark 1000 lookup 99
		1061	@end example
		1062
1049	@end itemize	1063	@end itemize
1050		1064
1051		1065
1052		1066
1053	@subsection NODE SPECIFIC SETTINGS	1067	@subsection NODE SPECIFIC SETTINGS
…		…
1068		1082
1069	@item	1083	@item
1070	compress = yes\|true\|on \| no\|false\|off	1084	compress = yes\|true\|on \| no\|false\|off
1071		1085
1072	@cindex compress	1086	@cindex compress
1073	Wether to compress data packets sent to this node (default: @t{yes}). Compression is really cheap even on slow computers and has no size overhead at all, so enabling this is a good idea.	1087	For the current node, this specified whether it will accept compressed packets, and for all other nodes, this specifies whether to try to compress data packets sent to this node (default: @t{yes}). Compression is really cheap even on slow computers, has no size overhead at all and will only be used when the other side supports compression, so enabling this is often a good idea.
1074	@refill	1088	@refill
1075		1089
1076		1090
1077	@item	1091	@item
1078	connect = ondemand \| never \| always \| disabled	1092	connect = ondemand \| never \| always \| disabled
…		…
1088	deny-direct = nodename \| *	1102	deny-direct = nodename \| *
1089		1103
1090	@cindex deny-direct	1104	@cindex deny-direct
1091	Deny direct connections to the specified node (or all nodes when @t{*} is given). Only one node can be specified, but you can use multiple @t{allow-direct} and @t{deny-direct} statements. This only makes sense in networks with routers, as routers are required for indirect connections.	1105	Deny direct connections to the specified node (or all nodes when @t{*} is given). Only one node can be specified, but you can use multiple @t{allow-direct} and @t{deny-direct} statements. This only makes sense in networks with routers, as routers are required for indirect connections.
1092	@refill	1106	@refill
1093	Sometimes, a node cannot reach some other nodes for reasons of network connectivity. For example, a node behind a firewall that only allows conenctions to/from a single other node in the network. In this case one should specify @t{deny-direct = *} and @t{allow-direct = othernodename} (the other node @emph{must} be a router for this to work).	1107	Sometimes, a node cannot reach some other nodes for reasons of network connectivity. For example, a node behind a firewall that only allows connections to/from a single other node in the network. In this case one should specify @t{deny-direct = *} and @t{allow-direct = othernodename} (the other node @emph{must} be a router for this to work).
1094	@refill	1108	@refill
1095	The algorithm to check wether a connection may be direct is as follows:	1109	The algorithm to check whether a connection may be direct is as follows:
1096	@refill	1110	@refill
1097	1. Other node mentioned in a @t{allow-direct}? If yes, allow the connection.	1111	1. Other node mentioned in an @t{allow-direct}? If yes, allow the connection.
1098	@refill	1112	@refill
1099	2. Other node mentioned in a @t{deny-direct}? If yes, deny direct connections.	1113	2. Other node mentioned in a @t{deny-direct}? If yes, deny direct connections.
1100	@refill	1114	@refill
1101	3. Allow the connection.	1115	3. Allow the connection.
1102	@refill	1116	@refill
…		…
1162	enable-icmp = yes\|true\|on \| no\|false\|off	1176	enable-icmp = yes\|true\|on \| no\|false\|off
1163		1177
1164	@cindex enable-icmp	1178	@cindex enable-icmp
1165	See gvpe.protocol(7) for a description of the ICMP transport protocol.	1179	See gvpe.protocol(7) for a description of the ICMP transport protocol.
1166	@refill	1180	@refill
1167	Enable the ICMP transport using icmp packets of type @t{icmp-type} on this node.	1181	Enable the ICMP transport using ICMP packets of type @t{icmp-type} on this node.
1168	@refill	1182	@refill
1169		1183
1170		1184
1171	@item	1185	@item
1172	enable-rawip = yes\|true\|on \| no\|false\|off	1186	enable-rawip = yes\|true\|on \| no\|false\|off
…		…
1194	@cindex enable-udp	1208	@cindex enable-udp
1195	See gvpe.protocol(7) for a description of the UDP transport protocol.	1209	See gvpe.protocol(7) for a description of the UDP transport protocol.
1196	@refill	1210	@refill
1197	Enable the UDPv4 transport using the @t{udp-port} port (default: @t{no}, unless no other protocol is enabled for a node, in which case this protocol is enabled automatically).	1211	Enable the UDPv4 transport using the @t{udp-port} port (default: @t{no}, unless no other protocol is enabled for a node, in which case this protocol is enabled automatically).
1198	@refill	1212	@refill
1199	NOTE: Please specify @t{enable-udp = yes} if you want t use it even though it might get switched on automatically, as some future version might default to another default protocol.	1213	NOTE: Please specify @t{enable-udp = yes} if you want to use it even though it might get switched on automatically, as some future version might default to another default protocol.
1200	@refill	1214	@refill
1201		1215
1202		1216
1203	@item	1217	@item
1204	hostname = hostname \| ip [can not be defaulted]	1218	hostname = hostname \| ip [can not be defaulted]
1205		1219
1206	@cindex hostname	1220	@cindex hostname
1207	Forces the address of this node to be set to the given dns hostname or ip address. It will be resolved before each connect request, so dyndns should work fine. If this setting is not specified and a router is available, then the router will be queried for the address of this node. Otherwise, the connection attempt will fail.	1221	Forces the address of this node to be set to the given DNS hostname or IP address. It will be resolved before each connect request, so dyndns should work fine. If this setting is not specified and a router is available, then the router will be queried for the address of this node. Otherwise, the connection attempt will fail.
		1222	@refill
		1223	Note that DNS resolving is done synchronously, pausing the daemon. If that is an issue you need to specify IP addresses.
1208	@refill	1224	@refill
1209		1225
1210		1226
1211	@item	1227	@item
1212	icmp-type = integer	1228	icmp-type = integer
1213		1229
1214	@cindex icmp-type	1230	@cindex icmp-type
1215	Sets the type value to be used for outgoing (and incoming) packets sent via the ICMP transport.	1231	Sets the type value to be used for outgoing (and incoming) packets sent via the ICMP transport.
1216	@refill	1232	@refill
1217	The default is @t{0} (which is @t{echo-reply}, also known as "ping-replies"). Other useful values include @t{8} (@t{echo-request}, a.k.a. "ping") and @t{11} (@t{time-exceeded}), but any 8-bit value can be used.	1233	The default is @t{0} (which is @t{echo-reply}, also known as "ping-reply"). Other useful values include @t{8} (@t{echo-request}, a.k.a. "ping") and @t{11} (@t{time-exceeded}), but any 8-bit value can be used.
1218	@refill	1234	@refill
1219		1235
1220		1236
1221	@item	1237	@item
1222	if-up-data = value	1238	if-up-data = value
…		…
1228		1244
1229	@item	1245	@item
1230	inherit-tos = yes\|true\|on \| no\|false\|off	1246	inherit-tos = yes\|true\|on \| no\|false\|off
1231		1247
1232	@cindex inherit-tos	1248	@cindex inherit-tos
1233	Wether to inherit the TOS settings of packets sent to the tunnel when sending packets to this node (default: @t{yes}). If set to @t{yes} then outgoing tunnel packets will have the same TOS setting as the packets sent to the tunnel device, which is usually what you want.	1249	Whether to inherit the TOS settings of packets sent to the tunnel when sending packets to this node (default: @t{yes}). If set to @t{yes} then outgoing tunnel packets will have the same TOS setting as the packets sent to the tunnel device, which is usually what you want.
1234	@refill	1250	@refill
1235		1251
1236		1252
1237	@item	1253	@item
1238	max-retry = positive-number	1254	max-retry = positive-number
1239		1255
1240	@cindex max-retry	1256	@cindex max-retry
1241	The maximum interval in seconds (default: @t{3600}, one hour) between retries to establish a connection to this node. When a connection cannot be established, gvpe uses exponential backoff capped at this value. It's sometimes useful to set this to a much lower value (e.g. @t{120}) on connections to routers that usually are stable but sometimes are down, to assure quick reconnections even after longer downtimes.	1257	The maximum interval in seconds (default: @t{3600}, one hour) between retries to establish a connection to this node. When a connection cannot be established, gvpe uses exponential back-off capped at this value. It's sometimes useful to set this to a much lower value (e.g. @t{120}) on connections to routers that usually are stable but sometimes are down, to assure quick reconnections even after longer downtimes.
1242	@refill	1258	@refill
1243		1259
1244		1260
1245	@item	1261	@item
1246	max-ttl = seconds	1262	max-ttl = seconds
…		…
1301		1317
1302	@itemize	1318	@itemize
1303		1319
1304		1320
1305	@item	1321	@item
1306
1307	@cindex gvpe.conf
1308	gvpe.conf	1322	gvpe.conf
1309		1323
1310	The config file.	1324	The config file.
1311	@refill	1325	@refill
1312		1326
1313		1327
1314	@item	1328	@item
1315
1316	@cindex if-up
1317	if-up	1329	if-up
1318		1330
1319	The if-up script	1331	The if-up script
1320	@refill	1332	@refill
1321		1333
1322		1334
1323	@item	1335	@item
1324		1336	node-up, node-down
1325	@cindex node-up
1326	node-up,
1327	@cindex node-down
1328	node-down
1329		1337
1330	If used the node up or node-down scripts.	1338	If used the node up or node-down scripts.
1331	@refill	1339	@refill
1332		1340
1333		1341
1334	@item	1342	@item
1335
1336	@cindex hostkey
1337	hostkey	1343	hostkey
1338		1344
1339	The private key (taken from @t{hostkeys/nodename}) of the current host.	1345	The private key (taken from @t{hostkeys/nodename}) of the current host.
1340	@refill	1346	@refill
1341		1347
1342		1348
1343	@item	1349	@item
1344
1345	@cindex pubkey/nodename
1346	pubkey/nodename	1350	pubkey/nodename
1347		1351
1348	The public keys of the other nodes, one file per node.	1352	The public keys of the other nodes, one file per node.
1349	@refill	1353	@refill
1350	@end itemize	1354	@end itemize
…		…
1385		1389
1386		1390
1387	@item	1391	@item
1388	@strong{-g}, @strong{--generate-keys}	1392	@strong{-g}, @strong{--generate-keys}
1389		1393
1390	Generate public/private RSA keypair and exit.	1394	Generate public/private RSA key-pair and exit.
1391	@refill	1395	@refill
1392		1396
1393		1397
1394	@item	1398	@item
1395	@strong{-q}, @strong{--quiet}	1399	@strong{-q}, @strong{--quiet}
…		…
1447	@t{gvpe} [@strong{-cDlL}] [@strong{--config=}@emph{DIR}] [@strong{--no-detach}] [@strong{-l=}@emph{LEVEL]}] [@strong{--kill}[@strong{=}@emph{SIGNAL}]] [@strong{--mlock}] [@strong{--help}] [@strong{--version}] @emph{NODENAME} [@emph{option...}]	1451	@t{gvpe} [@strong{-cDlL}] [@strong{--config=}@emph{DIR}] [@strong{--no-detach}] [@strong{-l=}@emph{LEVEL]}] [@strong{--kill}[@strong{=}@emph{SIGNAL}]] [@strong{--mlock}] [@strong{--help}] [@strong{--version}] @emph{NODENAME} [@emph{option...}]
1448	@refill	1452	@refill
1449		1453
1450		1454
1451	@section DESCRIPTION	1455	@section DESCRIPTION
1452	See the gvpe(5) manpage for an introduction to the gvpe suite.	1456	See the gvpe(5) man page for an introduction to the gvpe suite.
1453	@refill	1457	@refill
1454	This is the manual page for gvpe, the virtual private ethernet daemon. When started, @t{gvpe} will read it's configuration file to determine the network topology, and other configuration information, assuming the role of node @emph{NODENAME}. It will then connect to the tun/tap device and set up a socket for incoming connections. Then a script will be executed to further configure the virtual device. If that succeeds, it will detach from the controlling terminal and continue in the background, accepting and setting up connections to other gvpe daemons that are part of the virtual private ethernet.	1458	This is the manual page for gvpe, the virtual private ethernet daemon. When started, @t{gvpe} will read it's configuration file to determine the network topology, and other configuration information, assuming the role of node @emph{NODENAME}
		1459	@refill
		1460	It will then create/connect to the tun/tap device and set up a socket for incoming connections. Then a @t{if-up} script will be executed to further configure the virtual network device. If that succeeds, it will detach from the controlling terminal and continue in the background, accepting and setting up connections to other gvpe daemons that are part of the same virtual private ethernet.
1455	@refill	1461	@refill
1456	The optional arguments after the node name have to be of the form:	1462	The optional arguments after the node name have to be of the form:
1457	@refill	1463	@refill
1458		1464
1459		1465
1460	@example	1466	@example
1461	[I<nodename>.]var=value	1467	[I<nodename>.]var=value
1462	@end example	1468	@end example
1463		1469
1464	If the argument has a prefix of @t{nodename.} (i.e. @t{laptop.enable-dns=yes}) then it will be parsed after all the config directives for that node, if not, it is parsed befroe the first node directive in the config file, and can be used to set global options or default variables.	1470	If the argument has a prefix of @t{nodename.} (i.e. @t{laptop.enable-dns=yes}) then it will be parsed after all the config directives for that node, if not, it is parsed before the first node directive in the config file, and can be used to set global options or default variables.
1465	@refill	1471	@refill
1466	For example, to start @t{gvpe} in the foreground, with log-level @t{info} on the node @t{laptop}, with TCP enabled and HTTP-Proxy host and Port set, use this:	1472	For example, to start @t{gvpe} in the foreground, with log-level @t{info} on the node @t{laptop}, with TCP enabled and HTTP-Proxy host and Port set, use this:
1467	@refill	1473	@refill
1468		1474
1469		1475
…		…
1510		1516
1511		1517
1512	@item	1518	@item
1513	@strong{-L}, @strong{--mlock}	1519	@strong{-L}, @strong{--mlock}
1514		1520
1515	Lock @t{gvpe} into main memory. This will prevent sensitive data like shared private keys to be written to the system swap files/partitions.	1521	Lock @t{gvpe} into main memory. This will prevent sensitive data like shared private keys to be written to the system swap files/partitions.
1516	@refill	1522	@refill
1517		1523
1518		1524
1519	@item	1525	@item
1520	@strong{--version}	1526	@strong{--version}
…		…
1634		1640
1635		1641
1636	@subsection RAW IP	1642	@subsection RAW IP
1637	This protocol is the best choice, performance-wise, as the minimum overhead per packet is only 38 bytes.	1643	This protocol is the best choice, performance-wise, as the minimum overhead per packet is only 38 bytes.
1638	@refill	1644	@refill
1639	It works by sending the VPN payload using raw ip frames (using the protocol set by @t{ip-proto}).	1645	It works by sending the VPN payload using raw IP frames (using the protocol set by @t{ip-proto}).
1640	@refill	1646	@refill
1641	Using raw ip frames has the drawback that many firewalls block "unknown" protocols, so this transport only works if you have full IP connectivity between nodes.	1647	Using raw IP frames has the drawback that many firewalls block "unknown" protocols, so this transport only works if you have full IP connectivity between nodes.
1642	@refill	1648	@refill
1643		1649
1644		1650
1645	@subsection ICMP	1651	@subsection ICMP
1646	This protocol offers very low overhead (minimum 42 bytes), and can sometimes tunnel through firewalls when other protocols can not.	1652	This protocol offers very low overhead (minimum 42 bytes), and can sometimes tunnel through firewalls when other protocols can not.
1647	@refill	1653	@refill
1648	It works by prepending an ICMP header with type @t{icmp-type} and a code of @t{255}. The default @t{icmp-type} is @t{echo-reply}, so the resulting packets look like echo replies, which looks rather strange to network admins.	1654	It works by prepending an ICMP header with type @t{icmp-type} and a code of @t{255}. The default @t{icmp-type} is @t{echo-reply}, so the resulting packets look like echo replies, which looks rather strange to network administrators.
1649	@refill	1655	@refill
1650	This transport should only be used if other transports (i.e. raw ip) are not available or undesirable (due to their overhead).	1656	This transport should only be used if other transports (i.e. raw IP) are not available or undesirable (due to their overhead).
1651	@refill	1657	@refill
1652		1658
1653		1659
1654	@subsection UDP	1660	@subsection UDP
1655	This is a good general choice for the transport protocol as UDP packets tunnel well through most firewalls and routers, and the overhead per packet is moderate (minimum 58 bytes).	1661	This is a good general choice for the transport protocol as UDP packets tunnel well through most firewalls and routers, and the overhead per packet is moderate (minimum 58 bytes).
…		…
1676	@refill	1682	@refill
1677	In addition, the same problems as the TCP transport also plague this protocol.	1683	In addition, the same problems as the TCP transport also plague this protocol.
1678	@refill	1684	@refill
1679	It's only use is to tunnel through firewalls that do not allow direct internet access. Similar to using a HTTP proxy (as the TCP transport does), it uses a local DNS server/forwarder (given by the @t{dns-forw-host} configuration value) as a proxy to send and receive data as a client, and an @t{NS} record pointing to the GVPE server (as given by the @t{dns-hostname} directive).	1685	It's only use is to tunnel through firewalls that do not allow direct internet access. Similar to using a HTTP proxy (as the TCP transport does), it uses a local DNS server/forwarder (given by the @t{dns-forw-host} configuration value) as a proxy to send and receive data as a client, and an @t{NS} record pointing to the GVPE server (as given by the @t{dns-hostname} directive).
1680	@refill	1686	@refill
1681	The only good side of this protocol is that it can tunnel through most firewalls mostly undetected, iff the local DNS server/forwarder is sane (which is true for most routers, WLAN gateways and nameservers).	1687	The only good side of this protocol is that it can tunnel through most firewalls mostly undetected, iff the local DNS server/forwarder is sane (which is true for most routers, wireless LAN gateways and nameservers).
1682	@refill	1688	@refill
1683	Finetuning needs to be done by editing @t{src/vpn_dns.C} directly.	1689	Fine-tuning needs to be done by editing @t{src/vpn_dns.C} directly.
1684	@refill	1690	@refill
1685		1691
1686		1692
1687	@section PART 2: The GNU VPE protocol	1693	@section PART 2: The GNU VPE protocol
1688	This section, unfortunately, is not yet finished, although the protocol is stable (until bugs in the cryptography are found, which will likely completely change the following description). Nevertheless, it should give you some overview over the protocol.	1694	This section, unfortunately, is not yet finished, although the protocol is stable (until bugs in the cryptography are found, which will likely completely change the following description). Nevertheless, it should give you some overview over the protocol.
1689	@refill	1695	@refill
1690		1696
1691		1697
1692	@subsection Anatomy of a VPN packet	1698	@subsection Anatomy of a VPN packet
1693	The exact layout and field lengths of a VPN packet is determined at compiletime and doesn't change. The same structure is used for all transort protocols, be it RAWIP or TCP.	1699	The exact layout and field lengths of a VPN packet is determined at compile time and doesn't change. The same structure is used for all transport protocols, be it RAWIP or TCP.
1694	@refill	1700	@refill
1695		1701
1696		1702
1697	@example	1703	@example
1698	+------+------+--------+------+	1704	+------+------+--------+------+
…		…
1721	SEQNO is a 32-bit sequence number. It is negotiated at every connection initialization and starts at some random 31 bit value. VPE currently uses a sliding window of 512 packets/sequence numbers to detect reordering, duplication and replay attacks.	1727	SEQNO is a 32-bit sequence number. It is negotiated at every connection initialization and starts at some random 31 bit value. VPE currently uses a sliding window of 512 packets/sequence numbers to detect reordering, duplication and replay attacks.
1722	@refill	1728	@refill
1723		1729
1724		1730
1725	@subsection The authentication protocol	1731	@subsection The authentication protocol
1726	Before hosts can exchange packets, they need to establish authenticity of the other side and a key. Every host has a private RSA key and the public RSA keys of all other hosts.	1732	Before nodes can exchange packets, they need to establish authenticity of the other side and a key. Every node has a private RSA key and the public RSA keys of all other nodes.
1727	@refill	1733	@refill
1728	A host establishes a simplex connection by sending the other host an RSA encrypted challenge containing a random challenge (consisting of the encryption key to use when sending packets, more random data and PKCS1_OAEP padding) and a random 16 byte "challenge-id" (used to detect duplicate auth packets). The destination host will respond by replying with an (unencrypted) RIPEMD160 hash of the decrypted challenge, which will authenticate that host. The destination host will also set the outgoing encryption parameters as given in the packet.	1734	A host establishes a simplex connection by sending the other node an RSA encrypted challenge containing a random challenge (consisting of the encryption key to use when sending packets, more random data and PKCS1_OAEP padding) and a random 16 byte "challenge-id" (used to detect duplicate auth packets). The destination node will respond by replying with an (unencrypted) RIPEMD160 hash of the decrypted challenge, which will authenticate that node. The destination node will also set the outgoing encryption parameters as given in the packet.
1729	@refill	1735	@refill
1730	When the source host receives a correct auth reply (by verifying the hash and the id, which will expire after 120 seconds), it will start to accept data packets from the destination host.	1736	When the source node receives a correct auth reply (by verifying the hash and the id, which will expire after 120 seconds), it will start to accept data packets from the destination node.
1731	@refill	1737	@refill
1732	This means that a host can only initate a simplex connection, telling the other side the key it has to use when it sends packets. The challenge reply is only used to set the current IP address of the other side and protocol parameters.	1738	This means that a node can only initiate a simplex connection, telling the other side the key it has to use when it sends packets. The challenge reply is only used to set the current IP address of the other side and protocol parameters.
1733	@refill	1739	@refill
1734	This protocol is completely symmetric, so to be able to send packets the destination host must send a challenge in the exact same way as already described (so, in essence, two simplex connections are created per host pair).	1740	This protocol is completely symmetric, so to be able to send packets the destination node must send a challenge in the exact same way as already described (so, in essence, two simplex connections are created per node pair).
1735	@refill	1741	@refill
1736		1742
1737		1743
1738	@subsection Retrying	1744	@subsection Retrying
1739	When there is no response to an auth request, the host will send auth requests in bursts with an exponential backoff. After some time it will resort to PING packets, which are very small (8 bytes + protocol header) and lightweight (no RSA operations required). A host that receives ping requests from an unconnected peer will respond by trying to create a connection.	1745	When there is no response to an auth request, the node will send auth requests in bursts with an exponential back-off. After some time it will resort to PING packets, which are very small (8 bytes + protocol header) and lightweight (no RSA operations required). A node that receives ping requests from an unconnected peer will respond by trying to create a connection.
1740	@refill	1746	@refill
1741	In addition to the exponential backoff, there is a global rate-limit on a per-IP base. It allows long bursts but will limit total packet rate to something like one control packet every ten seconds, to avoid accidental floods due to protocol problems (like a RSA key file mismatch between two hosts).	1747	In addition to the exponential back-off, there is a global rate-limit on a per-IP base. It allows long bursts but will limit total packet rate to something like one control packet every ten seconds, to avoid accidental floods due to protocol problems (like a RSA key file mismatch between two nodes).
1742	@refill	1748	@refill
1743	The intervals between retries are limited by the @t{max-retry} configuration value. A node with @t{connect} = @t{always} will always retry, a node with @t{connect} = @t{ondemand} will only try (and re-try) to connect as long as there are packets in the queue, usually this limits the retry period to @t{max-ttl} seconds.	1749	The intervals between retries are limited by the @t{max-retry} configuration value. A node with @t{connect} = @t{always} will always retry, a node with @t{connect} = @t{ondemand} will only try (and re-try) to connect as long as there are packets in the queue, usually this limits the retry period to @t{max-ttl} seconds.
1744	@refill	1750	@refill
1745	Sending packets over the VPN will reset the retry intervals as well, which means as long as somebody is trying to send packets to a given node, GVPE will try to connect every few seconds.	1751	Sending packets over the VPN will reset the retry intervals as well, which means as long as somebody is trying to send packets to a given node, GVPE will try to connect every few seconds.
1746	@refill	1752	@refill
…		…
1753		1759
1754	@itemize	1760	@itemize
1755		1761
1756		1762
1757	@item	1763	@item
1758	If the two hosts should be able to reach each other directly (common protocol, port known), then GVPE will send the packet directly to the other node.	1764	If the two nodes should be able to reach each other directly (common protocol, port known), then GVPE will send the packet directly to the other node.
1759		1765
1760		1766
1761		1767
1762	@item	1768	@item
1763	If this isn't possible (e.g. because the node doesn't have a @t{hostname} or known port), but the nodes speak a common protocol and a router is available, then GVPE will ask a router to "mediate" between both nodes (see below).	1769	If this isn't possible (e.g. because the node doesn't have a @t{hostname} or known port), but the nodes speak a common protocol and a router is available, then GVPE will ask a router to "mediate" between both nodes (see below).
…		…
1779		1785
1780	@end itemize	1786	@end itemize
1781		1787
1782	A host can usually declare itself unreachable directly by setting it's port number(s) to zero. It can declare other hosts as unreachable by using a config-file that disables all protocols for these other hosts. Another option is to disable all protocols on that host in the other config files.	1788	A host can usually declare itself unreachable directly by setting it's port number(s) to zero. It can declare other hosts as unreachable by using a config-file that disables all protocols for these other hosts. Another option is to disable all protocols on that host in the other config files.
1783	@refill	1789	@refill
1784	If two hosts cannot connect to each other because their IP address(es) are not known (such as dialup hosts), one side will send a @emph{mediated} connection request to a router (routers must be configured to act as routers!), which will send both the originating and the destination host a connection info request with protocol information and IP address of the other host (if known). Both hosts will then try to establish a direct connection to the other peer, which is usually possible even when both hosts are behind a NAT gateway.	1790	If two hosts cannot connect to each other because their IP address(es) are not known (such as dial-up hosts), one side will send a @emph{mediated} connection request to a router (routers must be configured to act as routers!), which will send both the originating and the destination host a connection info request with protocol information and IP address of the other host (if known). Both hosts will then try to establish a direct connection to the other peer, which is usually possible even when both hosts are behind a NAT gateway.
1785	@refill	1791	@refill
1786	Routing via other nodes works because the SRCDST field is not encrypted, so the router can just forward the packet to the destination host. Since each host uses it's own private key, the router will not be able to decrypt or encrypt packets, it will just act as a simple router and protocol translator.	1792	Routing via other nodes works because the SRCDST field is not encrypted, so the router can just forward the packet to the destination host. Since each host uses it's own private key, the router will not be able to decrypt or encrypt packets, it will just act as a simple router and protocol translator.
1787	@refill	1793	@refill
1788		1794
1789		1795
…		…
1800	@example	1806	@example
1801	enable-udp = yes # use UDP	1807	enable-udp = yes # use UDP
1802	udp-port = 407 # use this UDP port	1808	udp-port = 407 # use this UDP port
1803	mtu = 1492 # handy for TDSL	1809	mtu = 1492 # handy for TDSL
1804	ifname = vpn0 # I prefer vpn0 over e.g. tap0	1810	ifname = vpn0 # I prefer vpn0 over e.g. tap0
1805	@end example
1806		1811
1807
1808
1809	@example
1810	node = huffy # arbitrary node name	1812	node = huffy # arbitrary node name
1811	hostname = 1.2.3.4 # ip address if this host	1813	hostname = 1.2.3.4 # ip address if this host
1812	@end example
1813		1814
1814
1815
1816	@example
1817	node = welshy	1815	node = welshy
1818	hostname = www.example.net # resolve at connection time	1816	hostname = www.example.net # resolve at connection time
1819	@end example
1820		1817
1821
1822
1823	@example
1824	node = wheelery	1818	node = wheelery
1825	# no hostname, will be determinded dynamically using router1 or router2	1819	# no hostname, will be determinded dynamically using router1 or router2
1826	@end example	1820	@end example
1827		1821
1828	@t{gvpe} will execute the @t{if-up} script on every hosts, which, for linux, could look like this for all three hosts:	1822	@t{gvpe} will execute the @t{if-up} script on every hosts, which, for linux, could look like this for all three hosts:

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Comparing gvpe/doc/gvpe.texi (file contents): Revision 1.4 by pcg, Mon Sep 1 05:31:28 2008 UTC vs. Revision 1.5 by root, Tue Feb 15 13:31:22 2011 UTC

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Comparing gvpe/doc/gvpe.texi (file contents):
Revision 1.4 by pcg, Mon Sep 1 05:31:28 2008 UTC vs.
Revision 1.5 by root, Tue Feb 15 13:31:22 2011 UTC