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Revision 1.5 by pcg, Tue Mar 1 06:27:20 2005 UTC vs.
Revision 1.35 by root, Fri Oct 11 07:56:07 2013 UTC

2 2
3gvpe.conf - configuration file for the GNU VPE daemon 3gvpe.conf - configuration file for the GNU VPE daemon
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 # global options for all nodes
7 udp-port = 407 8 udp-port = 407
8 mtu = 1492 9 mtu = 1492
9 ifname = vpn0 10 ifname = vpn0
10 11
12 # first node is named branch1 and is at 1.2.3.4
11 node = branch1 13 node = branch1
12 hostname = 1.2.3.4 14 hostname = 1.2.3.4
13 15
16 # second node uses dns to resolve the address
14 node = branch2 17 node = branch2
15 hostname = www.example.net 18 hostname = www.example.net
16 udp-port = 500 # this host uses a different udp-port 19 udp-port = 500 # this host uses a different udp-port
17 20
21 # third node has no fixed ip address
18 node = branch3 22 node = branch3
19 connect = ondemand 23 connect = ondemand
20 24
21=head1 DESCRIPTION 25=head1 DESCRIPTION
22 26
23The gvpe config file consists of a series of lines that contain C<variable 27The gvpe config file consists of a series of lines that contain C<variable
24= value> pairs. Empty lines are ignored. Comments start with a C<#> and 28= value> pairs. Empty lines are ignored. Comments start with a C<#> and
25extend to the end of the line. They can be used on their own lines, or 29extend to the end of the line. They can be used on their own lines, or
26after any directives. Spaces are allowed before or after the C<=> sign or 30after any directives. Whitespace is allowed around the C<=> sign or after
27after values, but not within the variable names or values themselves. 31values, but not within the variable names or values themselves.
28 32
29The only exception to the above is the "on" directive that can prefix any 33All settings are applied "in order", that is, later settings of the same
30C<name = value> setting and will only "execute" it on the named node, or 34variable overwrite earlier ones.
31(if the nodename starts with "!") on all nodes except the named one.
32 35
33 name = value 36The only exceptions to the above are the following directives:
37
38=over 4
39
40=item node nodename
41
42Introduces a node section. The nodename is used to select the right
43configuration section and is the same string as is passed as an argument
44to the gvpe daemon.
45
46Multiple C<node> statements with the same node name are supported and will
47be merged together.
48
49=item global
50
51This statement switches back to the global section, which is mainly
52useful if you want to include a second config file, e..g for local
53customisations. To do that, simply include this at the very end of your
54config file:
55
56 global
57 include local.conf
58
59=item on nodename ...
60
61=item on !nodename ...
62
63You can prefix any configuration directive with C<on> and a nodename. GVPE
64will will only "execute" it on the named node, or (if the nodename starts
65with C<!>) on all nodes except the named one.
66
67Example: set the MTU to C<1450> everywhere, C<loglevel> to C<noise> on
68C<branch1>, and C<connect> to C<ondemand> everywhere but on branch2.
69
70 mtu = 1450
34 on branch1 loglevel = noise 71 on branch1 loglevel = noise
35 on !branch2 connect = ondemand 72 on !branch2 connect = ondemand
36 73
37All settings are executed "in order", that is, later settings of the same 74=item include relative-or-absolute-path
38variable overwrite earlier ones. 75
76Reads the specified file (the path must not contain whitespace or C<=>
77characters) and evaluate all config directives in it as if they were
78spelled out in place of the C<include> directive.
79
80The path is a printf format string, that is, you must escape any C<%>
81by doubling it, and you can have a single C<%s> inside, which will be
82replaced by the current nodename.
83
84Relative paths are interpreted relative to the GVPE config directory.
85
86Example: include the file F<local.conf> in the config directory on every
87node.
88
89 include local.conf
90
91Example: include a file F<conf/>nodenameF<.conf>
92
93 include conf/%s.conf
94
95=back
39 96
40=head1 ANATOMY OF A CONFIG FILE 97=head1 ANATOMY OF A CONFIG FILE
41 98
42Usually, a config file starts with global settings (like the udp port to 99Usually, a config file starts with a few global settings (like the UDP
43listen on), followed by node-specific sections that begin with a C<node = 100port to listen on), followed by node-specific sections that begin with a
44nickname> line. 101C<node = nickname> line.
45 102
46Every node that is part of the network must have a section that starts 103Every node that is part of the network must have a section that starts
47with C<node = nickname>. The number and order of the nodes is important 104with C<node = nickname>. The number and order of the nodes is important
48and must be the same on all hosts. It is not uncommon for node sections to 105and must be the same on all nodes. It is not uncommon for node sections to
49be completely empty - if the default values are right. 106be completely empty - if the default values are right.
50 107
51Node-specific settings can be used at any time. If used before the first 108Node-specific settings can be used at any time. If used before the first
52node section they will set the default values for all following nodes. 109node section they will set the default values for all following nodes.
53 110
60values on different nodes using C<on>), but will affect the behaviour of 117values on different nodes using C<on>), but will affect the behaviour of
61the gvpe daemon and all connections it creates. 118the gvpe daemon and all connections it creates.
62 119
63=over 4 120=over 4
64 121
65=item loglevel = noise|trace|debug|info|notice|warn|error|critical 122=item chroot = path or /
66 123
67Set the logging level. Connection established messages are logged at level 124Tells GVPE to chroot(2) to the specified path after reading all necessary
68C<info>, notable errors are logged with C<error>. Default is C<info>. 125files, binding to sockets and running the C<if-up> script, but before
126running C<node-up> or any other scripts.
69 127
70=item node = nickname 128The special path F</> instructs GVPE to create (and remove) an empty
129temporary directory to use as new root. This is most secure, but makes it
130impossible to use any scripts other than the C<if-up> one.
71 131
72Not really a config setting but introduces a node section. The nickname is 132=item chuid = numerical-uid
73used to select the right configuration section and must be passed as an
74argument to the gvpe daemon.
75 133
76=item private-key = relative-path-to-key 134=item chgid = numerical-gid
77 135
78Sets the path (relative to the config directory) to the private key 136These two options tell GVPE to change to the given user and/or group id
79(default: C<hostkey>). This is a printf format string so every C<%> must 137after reading all necessary files, binding to sockets and running the
80be doubled. A single C<%s> is replaced by the hostname, so you could 138C<if-up> script.
81use paths like C<hostkeys/%s> to fetch the files at the location where
82C<gvpectrl> puts them.
83 139
84Since only the private key file of the current node is used and the 140Other scripts, such as C<node-up>, are run with the new user id or group id.
85private key file should be kept secret per-host to avoid spoofings, it is 141
86not recommended to use this feature. 142=item chuser = username
143
144Alternative to C<chuid> and C<chgid>: Sets both C<chuid> and C<chgid>
145to the user and (primary) group ids of the specified user (for example,
146C<nobody>).
147
148=item dns-forw-host = hostname/ip
149
150The DNS server to forward DNS requests to for the DNS tunnel protocol
151(default: C<127.0.0.1>, changing it is highly recommended).
152
153=item dns-forw-port = port-number
154
155The port where the C<dns-forw-host> is to be contacted (default: C<53>,
156which is fine in most cases).
157
158=item dns-case-preserving = yes|true|on | no|false|off
159
160Sets whether the DNS transport forwarding server preserves case (DNS
161servers have to, but some access systems are even more broken than others)
162(default: true).
163
164Normally, when the forwarding server changes the case of domain names then
165GVPE will automatically set this to false.
166
167=item dns-max-outstanding = integer-number-of-requests
168
169The maximum number of outstanding DNS transport requests
170(default: C<100>). GVPE will never issue more requests then the given
171limit without receiving replies. In heavily overloaded situations it might
172help to set this to a low number (e.g. C<3> or even C<1>) to limit the
173number of parallel requests.
174
175The default should be working OK for most links.
176
177=item dns-overlap-factor = float
178
179The DNS transport uses the minimum request latency (B<min_latency>) seen
180during a connection as it's timing base. This factor (default: C<0.5>,
181must be > 0) is multiplied by B<min_latency> to get the maximum sending
182rate (= minimum send interval), i.e. a factor of C<1> means that a new
183request might be generated every B<min_latency> seconds, which means on
184average there should only ever be one outstanding request. A factor of
185C<0.5> means that GVPE will send requests twice as often as the minimum
186latency measured.
187
188For congested or picky DNS forwarders you could use a value nearer to or
189exceeding C<1>.
190
191The default should be working OK for most links.
192
193=item dns-send-interval = send-interval-in-seconds
194
195The minimum send interval (= maximum rate) that the DNS transport will
196use to send new DNS requests. GVPE will not exceed this rate even when
197the latency is very low. The default is C<0.01>, which means GVPE will
198not send more than 100 DNS requests per connection per second. For
199high-bandwidth links you could go lower, e.g. to C<0.001> or so. For
200congested or rate-limited links, you might want to go higher, say C<0.1>,
201C<0.2> or even higher.
202
203The default should be working OK for most links.
204
205=item dns-timeout-factor = float
206
207Factor to multiply the C<min_latency> (see C<dns-overlap-factor>) by to
208get request timeouts. The default of C<8> means that the DNS transport
209will resend the request when no reply has been received for longer than
210eight times the minimum (= expected) latency, assuming the request or
211reply has been lost.
212
213For congested links a higher value might be necessary (e.g. C<30>). If
214the link is very stable lower values (e.g. C<2>) might work
215nicely. Values near or below C<1> makes no sense whatsoever.
216
217The default should be working OK for most links but will result in low
218throughput if packet loss is high.
219
220=item if-up = relative-or-absolute-path
221
222Sets the path of a script that should be called immediately after the
223network interface is initialized (but not necessarily up). The following
224environment variables are passed to it (the values are just examples).
225
226Variables that have the same value on all nodes:
227
228=over 4
229
230=item CONFBASE=/etc/gvpe
231
232The configuration base directory.
233
234=item IFNAME=vpn0
235
236The network interface to initialize.
237
238=item IFTYPE=native # or tincd
239
240=item IFSUBTYPE=linux # or freebsd, darwin etc..
241
242The interface type (C<native> or C<tincd>) and the subtype (usually the
243OS name in lowercase) that this GVPE was configured for. Can be used to
244select the correct syntax to use for network-related commands.
245
246=item MTU=1436
247
248The MTU to set the interface to. You can use lower values (if done
249consistently on all nodes), but this is usually either inefficient or
250simply ineffective.
251
252=item NODES=5
253
254The number of nodes in this GVPE network.
255
256=back
257
258Variables that are node-specific and with values pertaining to the node
259running this GVPE:
260
261=over 4
262
263=item IFUPDATA=string
264
265The value of the configuration directive C<if-up-data>.
266
267=item MAC=fe:fd:80:00:00:01
268
269The MAC address the network interface has to use.
270
271Might be used to initialize interfaces on platforms where GVPE does not
272do this automatically. Please see the C<gvpe.osdep(5)> man page for
273platform-specific information.
274
275=item NODENAME=branch1
276
277The nickname of the node.
278
279=item NODEID=1
280
281The numerical node ID of the node running this instance of GVPE. The first
282node mentioned in the config file gets ID 1, the second ID 2 and so on.
283
284=back
285
286In addition, all node-specific variables (except C<NODEID>) will be
287available with a postfix of C<_nodeid>, which contains the value for that
288node, e.g. the C<MAC_1> variable contains the MAC address of node #1, while
289the C<NODENAME_22> variable contains the name of node #22.
290
291Here is a simple if-up script:
292
293 #!/bin/sh
294 ip link set $IFNAME up
295 [ $NODENAME = branch1 ] && ip addr add 10.0.0.1 dev $IFNAME
296 [ $NODENAME = branch2 ] && ip addr add 10.1.0.1 dev $IFNAME
297 ip route add 10.0.0.0/8 dev $IFNAME
298
299More complicated examples (using routing to reduce ARP traffic) can be
300found in the F<etc/> subdirectory of the distribution.
301
302=item ifname = devname
303
304Sets the tun interface name to the given name. The default is OS-specific
305and most probably something like C<tun0>.
87 306
88=item ifpersist = yes|true|on | no|false|off 307=item ifpersist = yes|true|on | no|false|off
89 308
90Should the tun/tap device be made persistent, that is, should the device 309Should the tun/tap device be made persistent, that is, should the device
91stay up even when gvpe exits? Some versions of the tunnel device have 310stay up even when gvpe exits? Some versions of the tunnel device have
92problems sending packets when gvpe is restarted in persistent mode, so 311problems sending packets when gvpe is restarted in persistent mode, so
93if the connections can be established but you cannot send packets from 312if the connections can be established but you cannot send packets from
94the local node, try to set this to C<off> and do an ifconfig down on the 313the local node, try to set this to C<off> and do an ifconfig down on the
95device. 314device.
96 315
97=item ifname = devname
98
99Sets the tun interface name to the given name. The default is OS-specific
100and most probably something like C<tun0>.
101
102=item rekey = seconds
103
104Sets the rekeying interval in seconds (default: C<3600>). Connections are
105reestablished every C<rekey> seconds.
106
107=item keepalive = seconds
108
109Sets the keepalive probe interval in seconds (default: C<60>). After this
110many seconds of inactivity the daemon will start to send keepalive probe
111every 5 seconds until it receives a reply from the other end. If no reply
112is received within 30 seconds, the peer is considered unreachable and the
113connection is closed.
114
115=item mtu = bytes
116
117Sets the maximum MTU that should be used on outgoing packets (basically
118the MTU of the outgoing interface) The daemon will automatically calculate
119maximum overhead (e.g. udp header size, encryption blocksize...) and pass
120this information to the C<if-up> script.
121
122Recommended values are 1500 (ethernet), 1492 (pppoe), 1472 (pptp).
123
124This value must be the minimum of the mtu values of all hosts.
125
126=item ip-proto = numerical-ip-protocol 316=item ip-proto = numerical-ip-protocol
127 317
128Sets the protocol number to be used for the rawip protocol. This is a 318Sets the protocol number to be used for the rawip protocol. This is a
129global option because all hosts must use the same protocol, and since 319global option because all nodes must use the same protocol, and since
130there are no port numbers, you cannot easily run more than one gvpe 320there are no port numbers, you cannot easily run more than one gvpe
131instance using the same protocol, nor can you share the protocol with 321instance using the same protocol, nor can you share the protocol with
132other programs. 322other programs.
133 323
134The default is 47 (GRE), which has a good chance of tunneling through 324The default is 47 (GRE), which has a good chance of tunneling
135firewalls (but note that the rawip protocol is not GRE compatible). Other 325through firewalls (but note that gvpe's rawip protocol is not GRE
136common choices are 50 (IPSEC, ESP), 51 (IPSEC, AH), 4 (IPIP tunnels) or 98 326compatible). Other common choices are 50 (IPSEC, ESP), 51 (IPSEC, AH), 4
137(ENCAP, rfc1241) 327(IPIP tunnels) or 98 (ENCAP, rfc1241).
138 328
329Many versions of Linux seem to have a bug that causes them to reorder
330packets for some ip protocols (GRE, ESP) but not for others (AH), so
331choose wisely (that is, use 51, AH).
332
333=item http-proxy-host = hostname/ip
334
335The C<http-proxy-*> family of options are only available if gvpe was
336compiled with the C<--enable-http-proxy> option and enable tunneling of
337tcp connections through a http proxy server.
338
339C<http-proxy-host> and C<http-proxy-port> should specify the hostname and
340port number of the proxy server. See C<http-proxy-loginpw> if your proxy
341requires authentication.
342
343Please note that gvpe will still try to resolve all hostnames in the
344configuration file, so if you are behind a proxy without access to a DNS
345server better use numerical IP addresses.
346
347To make best use of this option disable all protocols except TCP in your
348config file and make sure your routers (or all other nodes) are listening
349on a port that the proxy allows (443, https, is a common choice).
350
351If you have a router, connecting to it will suffice. Otherwise TCP must be
352enabled on all nodes.
353
354Example:
355
356 http-proxy-host = proxy.example.com
357 http-proxy-port = 3128 # 8080 is another common choice
358 http-proxy-auth = schmorp:grumbeere
359
360=item http-proxy-port = proxy-tcp-port
361
362The port where your proxy server listens.
363
364=item http-proxy-auth = login:password
365
366The optional login and password used to authenticate to the proxy server,
367separated by a literal colon (C<:>). Only basic authentication is
368currently supported.
369
370=item keepalive = seconds
371
372Sets the keepalive probe interval in seconds (default: C<60>). After this
373many seconds of inactivity the daemon will start to send keepalive probe
374every 3 seconds until it receives a reply from the other end. If no reply
375is received within 15 seconds, the peer is considered unreachable and the
376connection is closed.
377
378=item loglevel = noise|trace|debug|info|notice|warn|error|critical
379
380Set the logging level. Connection established messages are logged at level
381C<info>, notable errors are logged with C<error>. Default is C<info>.
382
383=item mtu = bytes
384
385Sets the maximum MTU that should be used on outgoing packets (basically
386the MTU of the outgoing interface) The daemon will automatically calculate
387maximum overhead (e.g. UDP header size, encryption blocksize...) and pass
388this information to the C<if-up> script.
389
390Recommended values are 1500 (ethernet), 1492 (pppoe), 1472 (pptp).
391
392This value must be the minimum of the MTU values of all nodes.
393
394=item nfmark = integer
395
396This advanced option, when set to a nonzero value (default: C<0>), tries
397to set the netfilter mark (or fwmark) value on all sockets gvpe uses to
398send packets.
399
400This can be used to make gvpe use a different set of routing rules. For
401example, on GNU/Linux, the C<if-up> could set C<nfmark> to 1000 and then
402put all routing rules into table C<99> and then use an ip rule to make
403gvpe traffic avoid that routing table, in effect routing normal traffic
404via gvpe and gvpe traffic via the normal system routing tables:
405
406 ip rule add not fwmark 1000 lookup 99
407
139=item if-up = relative-or-absolute-path 408=item node-up = relative-or-absolute-path
140 409
141Sets the path of a script that should be called immediately after the 410Sets a command (default: none) that should be called whenever a connection
142network interface is initialized (but not neccessarily up). The following 411is established (even on rekeying operations). Note that node-up/down
412scripts will be run asynchronously, but execution is serialised, so there
413will only ever be one such script running.
414
415In addition to all the variables passed to C<if-up> scripts, the following
143environment variables are passed to it (the values are just examples): 416environment variables will be set (values are just examples):
144 417
145=over 4 418=over 4
146 419
147=item CONFBASE=/etc/gvpe
148
149The configuration base directory.
150
151=item IFNAME=vpn0
152
153The interface to initialize.
154
155=item MTU=1436
156
157The MTU to set the interface to. You can use lower values (if done
158consistently on all hosts), but this is usually ineffective.
159
160=item MAC=fe:fd:80:00:00:01
161
162The MAC address to set the interface to. The script *must* set the
163interface MAC to this value. You will most likely use one of these:
164
165 ip link set $IFNAME address $MAC mtu $MTU up # GNU/Linux
166 ifconfig $IFNAME ether $MAC mtu $MTU up # FreeBSD
167
168Please see the C<gvpe.osdep(5)> manpage for platform-specific information.
169
170=item IFTYPE=native # or tincd
171
172=item IFSUBTYPE=linux # or freebsd, darwin etc..
173
174The interface type (C<native> or C<tincd>) and the subtype (usually the os
175name in lowercase) that this gvpe was configured for. Can be used to select
176the correct syntax to use for network-related commands.
177
178=item NODENAME=branch1 420=item DESTNODE=branch2
179 421
180The nickname of the current node, as passed to the gvpe daemon. 422The name of the remote node.
181 423
182=item NODEID=1 424=item DESTID=2
183 425
184The numerical node id of the current node. The first node mentioned in the 426The node id of the remote node.
185config file gets ID 1, the second ID 2 and so on. 427
428=item DESTSI=rawip/88.99.77.55:0
429
430The "socket info" of the target node, protocol dependent but usually in
431the format protocol/ip:port.
432
433=item DESTIP=188.13.66.8
434
435The numerical IP address of the remote node (gvpe accepts connections from
436everywhere, as long as the other node can authenticate itself).
437
438=item DESTPORT=655 # deprecated
439
440The protocol port used by the other side, if applicable.
441
442=item STATE=up
443
444Node-up scripts get called with STATE=up, node-change scripts get called
445with STATE=change and node-down scripts get called with STATE=down.
186 446
187=back 447=back
188 448
189Here is a simple if-up script:
190
191 #!/bin/sh
192 ip link set $IFNAME address $MAC mtu $MTU up
193 [ $NODENAME = branch1 ] && ip addr add 10.0.0.1 dev $IFNAME
194 [ $NODENAME = branch2 ] && ip addr add 10.1.0.1 dev $IFNAME
195 ip route add 10.0.0.0/8 dev $IFNAME
196
197More complicated examples (using routing to reduce arp traffic) can be
198found in the etc/ subdirectory of the distribution.
199
200=item node-up = relative-or-absolute-path
201
202Sets a command (default: no script) that should be called whenever a
203connection is established (even on rekeying operations). In addition
204to the variables passed to C<if-up> scripts, the following environment
205variables will be set:
206
207=over 4
208
209=item DESTNODE=branch2
210
211The name of the remote node.
212
213=item DESTID=2
214
215The node id of the remote node.
216
217=item DESTIP=188.13.66.8
218
219The numerical IP address of the remote host (gvpe accepts connections from
220everywhere, as long as the other host can authenticate itself).
221
222=item DESTPORT=655 # deprecated
223
224The UDP port used by the other side.
225
226=item STATE=UP
227
228Node-up scripts get called with STATE=UP, node-down scripts get called
229with STATE=DOWN.
230
231=back
232
233Here is a nontrivial example that uses nsupdate to update the name => ip 449Here is a nontrivial example that uses nsupdate to update the name => ip
234mapping in some dns zone: 450mapping in some DNS zone:
235 451
236 #!/bin/sh 452 #!/bin/sh
237 { 453 {
238 echo update delete $DESTNODE.lowttl.example.net. a 454 echo update delete $DESTNODE.lowttl.example.net. a
239 echo update add $DESTNODE.lowttl.example.net. 1 in a $DESTIP 455 echo update add $DESTNODE.lowttl.example.net. 1 in a $DESTIP
240 echo 456 echo
241 } | nsupdate -d -k $CONFBASE:key.example.net. 457 } | nsupdate -d -k $CONFBASE:key.example.net.
242 458
459=item node-change = relative-or-absolute-path
460
461Same as C<node-change>, but gets called whenever something about a
462connection changes (such as the source IP address).
463
243=item node-down = relative-or-absolute-path 464=item node-down = relative-or-absolute-path
244 465
245Same as C<node-up>, but gets called whenever a connection is lost. 466Same as C<node-up>, but gets called whenever a connection is lost.
246 467
247=item http-proxy-host = hostname/ip
248
249The C<http-proxy-*> family of options are only available if gvpe was
250compiled with the C<--enable-http-proxy> option and enable tunneling of
251tcp connections through a http proxy server.
252
253C<http-proxy-host> and C<http-proxy-port> should specify the hostname and
254port number of the proxy server. See C<http-proxy-loginpw> if your proxy
255requires authentication.
256
257Please note that gvpe will still try to resolve all hostnames in the
258configuration file, so if you are behind a proxy without access to a dns
259server better use numerical IP addresses.
260
261To make best use of this option disable all protocols except tcp in your
262config file and make sure your routers (or all other hosts) are listening
263on a port that the proxy allows (443, https, is a common choice).
264
265If you have a router, connecting to it will suffice. Otherwise tcp must be
266enabled on all hosts.
267
268Example:
269
270 http-proxy-host = proxy.example.com
271 http-proxy-port = 3128 # 8080 is another common choice
272 http-proxy-auth = schmorp:grumbeere
273
274=item http-proxy-port = proxy-tcp-port
275
276The port where your proxy server listens.
277
278=item http-proxy-auth = login:password
279
280The optional login and password used to authenticate to the proxy server,
281seperated by a literal colon (C<:>). Only basic authentication is
282currently supported.
283
284=item pid-file = path 468=item pid-file = path
285 469
286The path to the pid file to check and create (Default: 470The path to the pid file to check and create
471(default: C<LOCALSTATEDIR/run/gvpe.pid>). The first C<%s> is replaced by
472the nodename - any other use of C<%> must be written as C<%%>.
473
474=item private-key = relative-path-to-key
475
476Sets the path (relative to the config directory) to the private key
477(default: C<hostkey>). This is a printf format string so every C<%> must
478be doubled. A single C<%s> is replaced by the hostname, so you could
479use paths like C<hostkeys/%s> to fetch the files at the location where
480C<gvpectrl> puts them.
481
482Since only the private key file of the current node is used and the
483private key file should be kept secret per-node to avoid spoofing, it is
484not recommended to use this feature.
485
486=item rekey = seconds
487
488Sets the rekeying interval in seconds (default: C<3607>). Connections are
489reestablished every C<rekey> seconds, making them use a new encryption
490key.
491
492=item seed-device = path
493
494The random device used to initially and regularly seed the random
495number generator (default: F</dev/urandom>). Randomness is of paramount
496importance to the security of the algorithms used in gvpe.
497
498On program start and every seed-interval, gvpe will read 64 octets.
499
500Setting this path to the empty string will disable this functionality
501completely (the underlying crypto library will likely look for entropy
502sources on it's own though, so not all is lost).
503
504=item seed-interval = seconds
505
506The number of seconds between reseeds of the random number generator
507(default: C<3613>). A value of C<0> disables this regular reseeding.
508
509=item serial = string
510
511The configuration serial number. This can be any string up to 16 bytes
512length. Only when the serial matches on both sides of a conenction will
513the connection succeed. This is I<not> a security mechanism and eay to
514spoof, this mechanism exists to alert users that their config is outdated.
515
516It's recommended to specify this is a date string such as C<2013-05-05> or
517C<20121205084417).
518
519The exact algorithm is as this: if a connection request is received form a
520node with an identical serial, then it succeeds normally.
521
522If the remote serial is lower than the local serial, it is ignored.
523
524If the remote serial is higher than the local serial, a warning message is
525logged.
287 526
288=back 527=back
289 528
290=head2 NODE SPECIFIC SETTINGS 529=head2 NODE SPECIFIC SETTINGS
291 530
292The following settings are node-specific, that is, every node can have 531The following settings are node-specific, that is, every node can have
293different settings, even within the same gvpe instance. Settings that are 532different settings, even within the same gvpe instance. Settings that are
294executed before the first node section set the defaults, settings that are 533set before the first node section set the defaults, settings that are
295executed within a node section only apply to the given node. 534set within a node section only apply to the given node.
296 535
297=over 4 536=over 4
298 537
538=item allow-direct = nodename
539
540Allow direct connections to this node. See C<deny-direct> for more info.
541
542=item compress = yes|true|on | no|false|off
543
544For the current node, this specified whether it will accept compressed
545packets, and for all other nodes, this specifies whether to try to
546compress data packets sent to this node (default: C<yes>). Compression is
547really cheap even on slow computers, has no size overhead at all and will
548only be used when the other side supports compression, so enabling this is
549often a good idea.
550
551=item connect = ondemand | never | always | disabled
552
553Sets the connect mode (default: C<always>). It can be C<always> (always
554try to establish and keep a connection to the given node), C<never>
555(never initiate a connection to the given host, but accept connections),
556C<ondemand> (try to establish a connection when there are outstanding
557packets in the queue and take it down after the keepalive interval) or
558C<disabled> (node is bad, don't talk to it).
559
560Routers will automatically be forced to C<always> unless they are
561C<disabled>, to ensure all nodes can talk to each other.
562
563=item deny-direct = nodename | *
564
565Deny direct connections to the specified node (or all nodes when C<*>
566is given). Only one node can be specified, but you can use multiple
567C<allow-direct> and C<deny-direct> statements. This only makes sense in
568networks with routers, as routers are required for indirect connections.
569
570Sometimes, a node cannot reach some other nodes for reasons of network
571connectivity. For example, a node behind a firewall that only allows
572connections to/from a single other node in the network. In this case one
573should specify C<deny-direct = *> and C<allow-direct = othernodename> (the other
574node I<must> be a router for this to work).
575
576The algorithm to check whether a connection may be direct is as follows:
577
5781. Other node mentioned in an C<allow-direct>? If yes, allow the connection.
579
5802. Other node mentioned in a C<deny-direct>? If yes, deny direct connections.
581
5823. Allow the connection.
583
584That is, C<allow-direct> takes precedence over C<deny-direct>.
585
586The check is done in both directions, i.e. both nodes must allow a direct
587connection before one is attempted, so you only need to specify connect
588limitations on one node.
589
590=item dns-domain = domain-suffix
591
592The DNS domain suffix that points to the DNS tunnel server for this node.
593
594The domain must point to a NS record that points to the I<dns-hostname>,
595i.e.
596
597 dns-domainname = tunnel.example.net
598 dns-hostname = tunnel-server.example.net
599
600Corresponds to the following DNS entries in the C<example.net> domain:
601
602 tunnel.example.net. NS tunnel-server.example.net.
603 tunnel-server.example.net. A 13.13.13.13
604
605=item dns-hostname = hostname/ip
606
607The address to bind the DNS tunnel socket to, similar to the C<hostname>,
608but for the DNS tunnel protocol only. Default: C<0.0.0.0>, but that might
609change.
610
299=item udp-port = port-number 611=item dns-port = port-number
300 612
301Sets the port number used by the UDP protocol (default: C<655>, not 613The port to bind the DNS tunnel socket to. Must be C<53> on DNS tunnel servers.
302officially assigned by IANA!).
303 614
304=item tcp-port = port-number 615=item enable-dns = yes|true|on | no|false|off
305 616
306Similar to C<udp-port> (default: C<655>), but sets the TCP port number. 617See gvpe.protocol(7) for a description of the DNS transport
618protocol. Avoid this protocol if you can.
619
620Enable the DNS tunneling protocol on this node, either as server or as
621client. Support for this transport protocol is only available when gvpe
622was compiled using the C<--enable-dns> option.
623
624=item enable-icmp = yes|true|on | no|false|off
625
626See gvpe.protocol(7) for a description of the ICMP transport protocol.
627
628Enable the ICMP transport using ICMP packets of type C<icmp-type> on this
629node.
307 630
308=item enable-rawip = yes|true|on | no|false|off 631=item enable-rawip = yes|true|on | no|false|off
309 632
633See gvpe.protocol(7) for a description of the RAW IP transport protocol.
634
310Enable the RAW IPv4 transport using the C<ip-proto> protocol 635Enable the RAW IPv4 transport using the C<ip-proto> protocol
311(default: C<no>). This is the best choice, since the overhead per packet 636(default: C<no>).
312is only 38 bytes, as opposed to UDP's 58 (or TCP's 60+). 637
638=item enable-tcp = yes|true|on | no|false|off
639
640See gvpe.protocol(7) for a description of the TCP transport protocol.
641
642Enable the TCPv4 transport using the C<tcp-port> port
643(default: C<no>). Support for this transport protocol is only available
644when gvpe was compiled using the C<--enable-tcp> option.
313 645
314=item enable-udp = yes|true|on | no|false|off 646=item enable-udp = yes|true|on | no|false|off
315 647
648See gvpe.protocol(7) for a description of the UDP transport protocol.
649
316Enable the UDPv4 transport using the C<udp-port> port (default: C<no>, 650Enable the UDPv4 transport using the C<udp-port> port (default: C<no>).
317unless no other protocol is enabled for a node, in which case this
318protocol is enabled automatically). This is a good general choice since
319UDP tunnels well through many firewalls.
320 651
321NOTE: Please specify C<enable-udp = yes> if you want t use it even though 652=item hostname = hostname | ip [can not be defaulted]
322it might get switched on automatically, as some future version might
323default to another default protocol.
324 653
325=item enable-tcp = yes|true|on | no|false|off 654Forces the address of this node to be set to the given DNS hostname or IP
655address. It will be resolved before each connect request, so dyndns should
656work fine. If this setting is not specified and a router is available,
657then the router will be queried for the address of this node. Otherwise,
658the connection attempt will fail.
326 659
327Enable the TCPv4 transport using the C<tcp-port> port 660Note that DNS resolving is done synchronously, pausing the daemon. If that
328(default: C<no>). Support for this horribly unsuitable protocol is only 661is an issue you need to specify IP addresses.
329available when gvpe was compiled using the C<--enable-tcp> option. Never
330use this transport unless you really must, it is horribly ineffiecent and
331resource-intensive compared to the other transports.
332 662
333=item router-priority = 0 | 1 | positive-number>2 663=item icmp-type = integer
334 664
335Sets the router priority of the given host (default: C<0>, disabled). If 665Sets the type value to be used for outgoing (and incoming) packets sent
336some host tries to connect to another host without a hostname, it asks 666via the ICMP transport.
337the router host for it's IP address. The router host is the one with the
338highest priority larger than C<1> that is currently reachable.
339 667
340Make sure all hosts always connect (C<connect = always>) to the router 668The default is C<0> (which is C<echo-reply>, also known as
341hosts, otherwise connecting to them might be impossible. 669"ping-reply"). Other useful values include C<8> (C<echo-request>, a.k.a.
670"ping") and C<11> (C<time-exceeded>), but any 8-bit value can be used.
342 671
343The special value C<1> allows other hosts to route through the router 672=item if-up-data = value
344host, but they will never route through it by default. The value C<0>
345disables routing. The idea behind this is that some hosts can, if
346required, bump the C<router-priority> setting to higher than C<1> in their
347local config to route through specific hosts. If C<router-priority> is
348C<0>, then routing will be refused, so C<1> serves as a "enable, but do
349not use by default" switch.
350 673
351=item connect = ondemand | never | always | disabled 674The value specified using this directive will be passed to the C<if-up>
352 675script in the environment variable C<IFUPDATA>.
353Sets the connect mode (default: C<always>). It can be C<always> (always
354try to establish and keep a connection to the given host), C<never>
355(never initiate a connection to the given host, but accept connections),
356C<ondemand> (try to establish a connection on the first packet sent, and
357take it down after the keepalive interval) or C<disabled> (node is bad,
358don't talk to it).
359 676
360=item inherit-tos = yes|true|on | no|false|off 677=item inherit-tos = yes|true|on | no|false|off
361 678
362Wether to inherit the TOS settings of packets sent to the tunnel when 679Whether to inherit the TOS settings of packets sent to the tunnel when
363sending packets to this node (default: C<yes>). If set to C<yes> then 680sending packets to this node (default: C<yes>). If set to C<yes> then
364outgoing tunnel packets will have the same TOS setting as the packets sent 681outgoing tunnel packets will have the same TOS setting as the packets sent
365to the tunnel device, which is usually what you want. 682to the tunnel device, which is usually what you want.
366 683
367=item compress = yes|true|on | no|false|off 684=item low-power = yes|true|on | no|false|off
368 685
369Wether to compress data packets sent to this host (default: C<yes>). 686If true, designates a node as a low-power node. Low-power nodes use
370Compression is really cheap even on slow computers and has no size 687larger timeouts and try to reduce cpu time. Other nodes talking to a
371overhead at all, so enabling this is a good idea. 688low-power node will also use larger timeouts, and will use less aggressive
689optimisations, in the hope of reducing load. Security is not compromised.
690
691The typical low-power node would be a mobile phone, where wakeups and
692encryption can significantly increase power drain.
372 693
373=item max-retry = positive-number 694=item max-retry = positive-number
374 695
375The maximum interval in seconds (default: C<28800>, 8 hours) between 696The maximum interval in seconds (default: C<3600>, one hour) between
376retries to establish a connection to this node. When a connection cannot 697retries to establish a connection to this node. When a connection cannot
377be established, gvpe uses exponential backoff capped at this value. It's 698be established, gvpe uses exponential back-off capped at this value. It's
378sometimes useful to set this to a much lower value (e.g. C<120>) on 699sometimes useful to set this to a much lower value (e.g. C<120>) on
379connections to routers that usually are stable but sometimes are down, to 700connections to routers that usually are stable but sometimes are down, to
380assure quick reconnections. 701assure quick reconnections even after longer downtimes.
702
703=item max-ttl = seconds
704
705Expire packets that couldn't be sent after this many seconds
706(default: C<60>). Gvpe will normally queue packets for a node without an
707active connection, in the hope of establishing a connection soon. This
708value specifies the maximum lifetime a packet will stay in the queue, if a
709packet gets older, it will be thrown away.
710
711=item max-queue = positive-number>=1
712
713The maximum number of packets that will be queued (default: C<512>)
714for this node. If more packets are sent then earlier packets will be
715expired. See C<max-ttl>, above.
716
717=item router-priority = 0 | 1 | positive-number>=2
718
719Sets the router priority of the given node (default: C<0>, disabled).
720
721If some node tries to connect to another node but it doesn't have a
722hostname, it asks a router node for it's IP address. The router node
723chosen is the one with the highest priority larger than C<1> that is
724currently reachable. This is called a I<mediated> connection, as the
725connection itself will still be direct, but it uses another node to
726mediate between the two nodes.
727
728The value C<0> disables routing, that means if the node receives a packet
729not for itself it will not forward it but instead drop it.
730
731The special value C<1> allows other hosts to route through the router
732host, but they will never route through it by default (i.e. the config
733file of another node needs to specify a router priority higher than one
734to choose such a node for routing).
735
736The idea behind this is that some hosts can, if required, bump the
737C<router-priority> setting to higher than C<1> in their local config to
738route through specific hosts. If C<router-priority> is C<0>, then routing
739will be refused, so C<1> serves as a "enable, but do not use by default"
740switch.
741
742Nodes with C<router-priority> set to C<2> or higher will always be forced
743to C<connect> = C<always> (unless they are C<disabled>).
744
745=item tcp-port = port-number
746
747Similar to C<udp-port> (default: C<655>), but sets the TCP port number.
748
749=item udp-port = port-number
750
751Sets the port number used by the UDP protocol (default: C<655>, not
752officially assigned by IANA!).
381 753
382=back 754=back
383 755
384=head1 CONFIG DIRECTORY LAYOUT 756=head1 CONFIG DIRECTORY LAYOUT
385 757
386The default (or recommended) directory layout for the config directory is: 758The default (or recommended) directory layout for the config directory is:
387 759
388=over 4 760=over 4
389 761
390=item X<gvpe.conf> 762=item gvpe.conf
391 763
392The config file. 764The config file.
393 765
394=item X<if-up> 766=item if-up
395 767
396The if-up script 768The if-up script
397 769
398=item X<node-up>, X<node-down> 770=item node-up, node-down
399 771
400If used the node up or node-down scripts. 772If used the node up or node-down scripts.
401 773
402=item X<hostkey> 774=item hostkey
403 775
404The private key (taken from C<hostkeys/nodename>) of the current host. 776The (default path of the) private key of the current host.
405 777
406=item X<pubkey/nodename> 778=item pubkey/nodename
407 779
408The public keys of the other nodes, one file per node. 780The public keys of the other nodes, one file per node.
409 781
410=back 782=back
411 783
413 785
414gvpe(5), gvpe(8), gvpectrl(8). 786gvpe(5), gvpe(8), gvpectrl(8).
415 787
416=head1 AUTHOR 788=head1 AUTHOR
417 789
418Marc Lehmann <gvpe@plan9.de> 790Marc Lehmann <gvpe@schmorp.de>
419 791

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