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Revision 1.1 by pcg, Fri Jun 11 15:56:13 2004 UTC vs.
Revision 1.32 by root, Tue Jul 16 16:44:36 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 enable-udp = yes 7 # global options for all nodes
8 udp-port = 407 8 udp-port = 407
9 mtu = 1492 9 mtu = 1492
10 ifname = vpn0 10 ifname = vpn0
11 11
12 # first node is named branch1 and is at 1.2.3.4
12 node = branch1 13 node = branch1
13 hostname = 1.2.3.4 14 hostname = 1.2.3.4
14 15
16 # second node uses dns to resolve the address
15 node = branch2 17 node = branch2
16 hostname = www.example.net 18 hostname = www.example.net
17 udp-port = 500 # this host uses a different udp-port 19 udp-port = 500 # this host uses a different udp-port
18 20
21 # third node has no fixed ip address
19 node = branch3 22 node = branch3
20 connect = ondemand 23 connect = ondemand
21 24
22=head1 DESCRIPTION 25=head1 DESCRIPTION
23 26
24The 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
25= 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
26extend 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
27after any directives. Spaces are allowed before or after the C<=> sign or 30after any directives. Whitespace is allowed around the C<=> sign or after
28after values, but not within the variable names or values themselves. 31values, but not within the variable names or values themselves.
29 32
30The 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
31C<name = value> setting and will only "execute" it on the named node, or 34variable overwrite earlier ones.
32(if the nodename starts with "!") on all nodes except the named one.
33 35
34 name = value 36The only exceptions to the above are the "on" and "include" directives:
37
38=over 4
39
40=item on nodename ...
41
42=item on !nodename ...
43
44You can prefix any configuration directive with C<on> and a nodename. GVPE
45will will only "execute" it on the named node, or (if the nodename starts
46with C<!>) on all nodes except the named one.
47
48Example: set the MTU to C<1450> everywhere, C<loglevel> to C<noise> on
49C<branch1>, and C<connect> to C<ondemand> everywhere but on branch2.
50
51 mtu = 1450
35 on branch1 loglevel = noise 52 on branch1 loglevel = noise
36 on !branch2 connect = ondemand 53 on !branch2 connect = ondemand
37 54
38All settings are executed "in order", that is, later settings of the same 55=item include relative-or-absolute-path
39variable overwrite earlier ones. 56
57Reads the specified file (the path must not contain whitespace or C<=>
58characters) and evaluate all config directives in it as if they were
59spelled out in place of the C<include> directive.
60
61The path is a printf format string, that is, you must escape any C<%>
62by doubling it, and you can have a single C<%s> inside, which will be
63replaced by the current nodename.
64
65Relative paths are interpreted relative to the GVPE config directory.
66
67Example: include the file F<local.conf> in the config directory on every
68node.
69
70 include local.conf
71
72Example: include a file F<conf/>nodenameF<.conf>
73
74 include conf/%s.conf
75
76=back
40 77
41=head1 ANATOMY OF A CONFIG FILE 78=head1 ANATOMY OF A CONFIG FILE
42 79
43Usually, a config file starts with global settings (like the udp port to 80Usually, a config file starts with a few global settings (like the UDP
44listen on), followed by node-specific sections that begin with a C<node = 81port to listen on), followed by node-specific sections that begin with a
45nickname> line. 82C<node = nickname> line.
46 83
47Every node that is part of the network must have a section that starts 84Every node that is part of the network must have a section that starts
48with C<node = nickname>. The number and order of the nodes is important 85with C<node = nickname>. The number and order of the nodes is important
49and must be the same on all hosts. It is not uncommon for node sections to 86and must be the same on all nodes. It is not uncommon for node sections to
50be completely empty - if the default values are right. 87be completely empty - if the default values are right.
51 88
52Node-specific settings can be used at any time. If used before the first 89Node-specific settings can be used at any time. If used before the first
53node section they will set the default values for all following nodes. 90node section they will set the default values for all following nodes.
54 91
61values on different nodes using C<on>), but will affect the behaviour of 98values on different nodes using C<on>), but will affect the behaviour of
62the gvpe daemon and all connections it creates. 99the gvpe daemon and all connections it creates.
63 100
64=over 4 101=over 4
65 102
66=item loglevel = noise|trace|debug|info|notice|warn|error|critical 103=item chroot = path or /
67 104
68Set the logging level. Connection established messages are logged at level 105Tells GVPE to chroot(2) to the specified path after reading all necessary
69C<info>, notable errors are logged with C<error>. Default is C<info>. 106files, binding to sockets and running the C<if-up> script, but before
107running C<node-up> or any other scripts.
70 108
71=item node = nickname 109The special path F</> instructs GVPE to create (and remove) an empty
110temporary directory to use as new root. This is most secure, but makes it
111impossible to use any scripts other than the C<if-up> one.
72 112
73Not really a config setting but introduces a node section. The nickname is 113=item chuid = numerical-uid
74used to select the right configuration section and must be passed as an
75argument to the gvpe daemon.
76 114
77=item private-key = relative-path-to-key 115=item chgid = numerical-gid
78 116
79Sets the path (relative to the config directory) to the private key 117These two options tell GVPE to change to the given user and/or group id
80(default: C<hostkey>). This is a printf format string so every C<%> must 118after reading all necessary files, binding to sockets and running the
81be doubled. A single C<%s> is replaced by the hostname, so you could 119C<if-up> script.
82use paths like C<hostkeys/%s> to fetch the files at the location where
83C<gvpectrl> puts them.
84 120
85Since only the private key file of the current node is used and the 121Other scripts, such as C<node-up>, are run with the new user id or group id.
86private key file should be kept secret per-host to avoid spoofings, it is 122
87not recommended to use this feature. 123=item chuser = username
124
125Alternative to C<chuid> and C<chgid>: Sets both C<chuid> and C<chgid>
126to the user and (primary) group ids of the specified user (for example,
127C<nobody>).
128
129=item dns-forw-host = hostname/ip
130
131The DNS server to forward DNS requests to for the DNS tunnel protocol
132(default: C<127.0.0.1>, changing it is highly recommended).
133
134=item dns-forw-port = port-number
135
136The port where the C<dns-forw-host> is to be contacted (default: C<53>,
137which is fine in most cases).
138
139=item dns-case-preserving = yes|true|on | no|false|off
140
141Sets whether the DNS transport forwarding server preserves case (DNS
142servers have to, but some access systems are even more broken than others)
143(default: true).
144
145Normally, when the forwarding server changes the case of domain names then
146GVPE will automatically set this to false.
147
148=item dns-max-outstanding = integer-number-of-requests
149
150The maximum number of outstanding DNS transport requests
151(default: C<100>). GVPE will never issue more requests then the given
152limit without receiving replies. In heavily overloaded situations it might
153help to set this to a low number (e.g. C<3> or even C<1>) to limit the
154number of parallel requests.
155
156The default should be working OK for most links.
157
158=item dns-overlap-factor = float
159
160The DNS transport uses the minimum request latency (B<min_latency>) seen
161during a connection as it's timing base. This factor (default: C<0.5>,
162must be > 0) is multiplied by B<min_latency> to get the maximum sending
163rate (= minimum send interval), i.e. a factor of C<1> means that a new
164request might be generated every B<min_latency> seconds, which means on
165average there should only ever be one outstanding request. A factor of
166C<0.5> means that GVPE will send requests twice as often as the minimum
167latency measured.
168
169For congested or picky DNS forwarders you could use a value nearer to or
170exceeding C<1>.
171
172The default should be working OK for most links.
173
174=item dns-send-interval = send-interval-in-seconds
175
176The minimum send interval (= maximum rate) that the DNS transport will
177use to send new DNS requests. GVPE will not exceed this rate even when
178the latency is very low. The default is C<0.01>, which means GVPE will
179not send more than 100 DNS requests per connection per second. For
180high-bandwidth links you could go lower, e.g. to C<0.001> or so. For
181congested or rate-limited links, you might want to go higher, say C<0.1>,
182C<0.2> or even higher.
183
184The default should be working OK for most links.
185
186=item dns-timeout-factor = float
187
188Factor to multiply the C<min_latency> (see C<dns-overlap-factor>) by to
189get request timeouts. The default of C<8> means that the DNS transport
190will resend the request when no reply has been received for longer than
191eight times the minimum (= expected) latency, assuming the request or
192reply has been lost.
193
194For congested links a higher value might be necessary (e.g. C<30>). If
195the link is very stable lower values (e.g. C<2>) might work
196nicely. Values near or below C<1> makes no sense whatsoever.
197
198The default should be working OK for most links but will result in low
199throughput if packet loss is high.
200
201=item if-up = relative-or-absolute-path
202
203Sets the path of a script that should be called immediately after the
204network interface is initialized (but not necessarily up). The following
205environment variables are passed to it (the values are just examples).
206
207Variables that have the same value on all nodes:
208
209=over 4
210
211=item CONFBASE=/etc/gvpe
212
213The configuration base directory.
214
215=item IFNAME=vpn0
216
217The network interface to initialize.
218
219=item IFTYPE=native # or tincd
220
221=item IFSUBTYPE=linux # or freebsd, darwin etc..
222
223The interface type (C<native> or C<tincd>) and the subtype (usually the
224OS name in lowercase) that this GVPE was configured for. Can be used to
225select the correct syntax to use for network-related commands.
226
227=item MTU=1436
228
229The MTU to set the interface to. You can use lower values (if done
230consistently on all nodes), but this is usually either inefficient or
231simply ineffective.
232
233=item NODES=5
234
235The number of nodes in this GVPE network.
236
237=back
238
239Variables that are node-specific and with values pertaining to the node
240running this GVPE:
241
242=over 4
243
244=item IFUPDATA=string
245
246The value of the configuration directive C<if-up-data>.
247
248=item MAC=fe:fd:80:00:00:01
249
250The MAC address the network interface has to use.
251
252Might be used to initialize interfaces on platforms where GVPE does not
253do this automatically. Please see the C<gvpe.osdep(5)> man page for
254platform-specific information.
255
256=item NODENAME=branch1
257
258The nickname of the node.
259
260=item NODEID=1
261
262The numerical node ID of the node running this instance of GVPE. The first
263node mentioned in the config file gets ID 1, the second ID 2 and so on.
264
265=back
266
267In addition, all node-specific variables (except C<NODEID>) will be
268available with a postfix of C<_nodeid>, which contains the value for that
269node, e.g. the C<MAC_1> variable contains the MAC address of node #1, while
270the C<NODENAME_22> variable contains the name of node #22.
271
272Here is a simple if-up script:
273
274 #!/bin/sh
275 ip link set $IFNAME up
276 [ $NODENAME = branch1 ] && ip addr add 10.0.0.1 dev $IFNAME
277 [ $NODENAME = branch2 ] && ip addr add 10.1.0.1 dev $IFNAME
278 ip route add 10.0.0.0/8 dev $IFNAME
279
280More complicated examples (using routing to reduce ARP traffic) can be
281found in the F<etc/> subdirectory of the distribution.
282
283=item ifname = devname
284
285Sets the tun interface name to the given name. The default is OS-specific
286and most probably something like C<tun0>.
88 287
89=item ifpersist = yes|true|on | no|false|off 288=item ifpersist = yes|true|on | no|false|off
90 289
91Should the tun/tap device be made persistent, that is, should the device 290Should the tun/tap device be made persistent, that is, should the device
92stay up even when gvpe exits? Some versions of the tunnel device have 291stay up even when gvpe exits? Some versions of the tunnel device have
93problems sending packets when gvpe is restarted in persistent mode, so 292problems sending packets when gvpe is restarted in persistent mode, so
94if the connections can be established but you cannot send packets from 293if the connections can be established but you cannot send packets from
95the local node, try to set this to C<off> and do an ifconfig down on the 294the local node, try to set this to C<off> and do an ifconfig down on the
96device. 295device.
97 296
98=item ifname = devname
99
100Sets the tun interface name to the given name. The default is OS-specific
101and most probably something like C<tun0>.
102
103=item rekey = seconds
104
105Sets the rekeying interval in seconds (default: C<3600>). Connections are
106reestablished every C<rekey> seconds.
107
108=item keepalive = seconds
109
110Sets the keepalive probe interval in seconds (default: C<60>). After this
111many seconds of inactivity the daemon will start to send keepalive probe
112every 5 seconds until it receives a reply from the other end. If no reply
113is received within 30 seconds, the peer is considered unreachable and the
114connection is closed.
115
116=item mtu = bytes
117
118Sets the maximum MTU that should be used on outgoing packets (basically
119the MTU of the outgoing interface) The daemon will automatically calculate
120maximum overhead (e.g. udp header size, encryption blocksize...) and pass
121this information to the C<if-up> script.
122
123Recommended values are 1500 (ethernet), 1492 (pppoe), 1472 (pptp).
124
125This value must be the minimum of the mtu values of all hosts.
126
127=item ip-proto = numerical-ip-protocol 297=item ip-proto = numerical-ip-protocol
128 298
129Sets the protocol number to be used for the rawip protocol. This is a 299Sets the protocol number to be used for the rawip protocol. This is a
130global option because all hosts must use the same protocol, and since 300global option because all nodes must use the same protocol, and since
131there are no port numbers, you cannot easily run more than one gvpe 301there are no port numbers, you cannot easily run more than one gvpe
132instance using the same protocol, nor can you share the protocol with 302instance using the same protocol, nor can you share the protocol with
133other programs. 303other programs.
134 304
135The default is 47 (GRE), which has a good chance of tunneling through 305The default is 47 (GRE), which has a good chance of tunneling
136firewalls (but note that the rawip protocol is not GRE compatible). Other 306through firewalls (but note that gvpe's rawip protocol is not GRE
137common choices are 50 (IPSEC, ESP), 51 (IPSEC, AH), 4 (IPIP tunnels) or 98 307compatible). Other common choices are 50 (IPSEC, ESP), 51 (IPSEC, AH), 4
138(ENCAP, rfc1241) 308(IPIP tunnels) or 98 (ENCAP, rfc1241).
139 309
310Many versions of Linux seem to have a bug that causes them to reorder
311packets for some ip protocols (GRE, ESP) but not for others (AH), so
312choose wisely (that is, use 51, AH).
313
314=item http-proxy-host = hostname/ip
315
316The C<http-proxy-*> family of options are only available if gvpe was
317compiled with the C<--enable-http-proxy> option and enable tunneling of
318tcp connections through a http proxy server.
319
320C<http-proxy-host> and C<http-proxy-port> should specify the hostname and
321port number of the proxy server. See C<http-proxy-loginpw> if your proxy
322requires authentication.
323
324Please note that gvpe will still try to resolve all hostnames in the
325configuration file, so if you are behind a proxy without access to a DNS
326server better use numerical IP addresses.
327
328To make best use of this option disable all protocols except TCP in your
329config file and make sure your routers (or all other nodes) are listening
330on a port that the proxy allows (443, https, is a common choice).
331
332If you have a router, connecting to it will suffice. Otherwise TCP must be
333enabled on all nodes.
334
335Example:
336
337 http-proxy-host = proxy.example.com
338 http-proxy-port = 3128 # 8080 is another common choice
339 http-proxy-auth = schmorp:grumbeere
340
341=item http-proxy-port = proxy-tcp-port
342
343The port where your proxy server listens.
344
345=item http-proxy-auth = login:password
346
347The optional login and password used to authenticate to the proxy server,
348separated by a literal colon (C<:>). Only basic authentication is
349currently supported.
350
351=item keepalive = seconds
352
353Sets the keepalive probe interval in seconds (default: C<60>). After this
354many seconds of inactivity the daemon will start to send keepalive probe
355every 3 seconds until it receives a reply from the other end. If no reply
356is received within 15 seconds, the peer is considered unreachable and the
357connection is closed.
358
359=item loglevel = noise|trace|debug|info|notice|warn|error|critical
360
361Set the logging level. Connection established messages are logged at level
362C<info>, notable errors are logged with C<error>. Default is C<info>.
363
364=item mtu = bytes
365
366Sets the maximum MTU that should be used on outgoing packets (basically
367the MTU of the outgoing interface) The daemon will automatically calculate
368maximum overhead (e.g. UDP header size, encryption blocksize...) and pass
369this information to the C<if-up> script.
370
371Recommended values are 1500 (ethernet), 1492 (pppoe), 1472 (pptp).
372
373This value must be the minimum of the MTU values of all nodes.
374
375=item nfmark = integer
376
377This advanced option, when set to a nonzero value (default: C<0>), tries
378to set the netfilter mark (or fwmark) value on all sockets gvpe uses to
379send packets.
380
381This can be used to make gvpe use a different set of routing rules. For
382example, on GNU/Linux, the C<if-up> could set C<nfmark> to 1000 and then
383put all routing rules into table C<99> and then use an ip rule to make
384gvpe traffic avoid that routing table, in effect routing normal traffic
385via gvpe and gvpe traffic via the normal system routing tables:
386
387 ip rule add not fwmark 1000 lookup 99
388
389=item node = nickname
390
391Not really a config setting but introduces a node section. The nickname is
392used to select the right configuration section and must be passed as an
393argument to the gvpe daemon.
394
140=item if-up = relative-or-absolute-path 395=item node-up = relative-or-absolute-path
141 396
142Sets the path of a script that should be called immediately after the 397Sets a command (default: none) that should be called whenever a connection
143network interface is initialized (but not neccessarily up). The following 398is established (even on rekeying operations). Note that node-up/down
399scripts will be run asynchronously, but execution is serialised, so there
400will only ever be one such script running.
401
402In addition to all the variables passed to C<if-up> scripts, the following
144environment variables are passed to it (the values are just examples): 403environment variables will be set (values are just examples):
145 404
146=over 4 405=over 4
147 406
148=item CONFBASE=/etc/gvpe
149
150The configuration base directory.
151
152=item IFNAME=vpn0
153
154The interface to initialize.
155
156=item MTU=1436
157
158The MTU to set the interface to. You can use lower values (if done
159consistently on all hosts), but this is usually ineffective.
160
161=item MAC=fe:fd:80:00:00:01
162
163The MAC address to set the interface to. The script *must* set the
164interface MAC to this value. You will most likely use one of these:
165
166 ip link set $IFNAME address $MAC mtu $MTU up # GNU/Linux
167 ifconfig $IFNAME ether $MAC mtu $MTU up # FreeBSD
168
169Please see the C<gvpe.osdep(5)> manpage for platform-specific information.
170
171=item IFTYPE=native # or tincd
172
173=item IFSUBTYPE=linux # or freebsd, darwin etc..
174
175The interface type (C<native> or C<tincd>) and the subtype (usually the os
176name in lowercase) that this gvpe was configured for. Can be used to select
177the correct syntax to use for network-related commands.
178
179=item NODENAME=branch1 407=item DESTNODE=branch2
180 408
181The nickname of the current node, as passed to the gvpe daemon. 409The name of the remote node.
182 410
183=item NODEID=1 411=item DESTID=2
184 412
185The numerical node id of the current node. The first node mentioned in the 413The node id of the remote node.
186config file gets ID 1, the second ID 2 and so on. 414
415=item DESTSI=rawip/88.99.77.55:0
416
417The "socket info" of the target node, protocol dependent but usually in
418the format protocol/ip:port.
419
420=item DESTIP=188.13.66.8
421
422The numerical IP address of the remote node (gvpe accepts connections from
423everywhere, as long as the other node can authenticate itself).
424
425=item DESTPORT=655 # deprecated
426
427The protocol port used by the other side, if applicable.
428
429=item STATE=up
430
431Node-up scripts get called with STATE=up, node-change scripts get called
432with STATE=change and node-down scripts get called with STATE=down.
187 433
188=back 434=back
189 435
190Here is a simple if-up script:
191
192 #!/bin/sh
193 ip link set $IFNAME address $MAC mtu $MTU up
194 [ $NODENAME = branch1 ] && ip addr add 10.0.0.1 dev $IFNAME
195 [ $NODENAME = branch2 ] && ip addr add 10.1.0.1 dev $IFNAME
196 ip route add 10.0.0.0/8 dev $IFNAME
197
198More complicated examples (using routing to reduce arp traffic) can be
199found in the etc/ subdirectory of the distribution.
200
201=item node-up = relative-or-absolute-path
202
203Sets a command (default: no script) that should be called whenever a
204connection is established (even on rekeying operations). In addition
205to the variables passed to C<if-up> scripts, the following environment
206variables will be set:
207
208=over 4
209
210=item DESTNODE=branch2
211
212The name of the remote node.
213
214=item DESTID=2
215
216The node id of the remote node.
217
218=item DESTIP=188.13.66.8
219
220The numerical IP address of the remote host (gvpe accepts connections from
221everywhere, as long as the other host can authenticate itself).
222
223=item DESTPORT=655 # deprecated
224
225The UDP port used by the other side.
226
227=item STATE=UP
228
229Node-up scripts get called with STATE=UP, node-down scripts get called
230with STATE=DOWN.
231
232=back
233
234Here is a nontrivial example that uses nsupdate to update the name => ip 436Here is a nontrivial example that uses nsupdate to update the name => ip
235mapping in some dns zone: 437mapping in some DNS zone:
236 438
237 #!/bin/sh 439 #!/bin/sh
238 { 440 {
239 echo update delete $DESTNODE.lowttl.example.net. a 441 echo update delete $DESTNODE.lowttl.example.net. a
240 echo update add $DESTNODE.lowttl.example.net. 1 in a $DESTIP 442 echo update add $DESTNODE.lowttl.example.net. 1 in a $DESTIP
241 echo 443 echo
242 } | nsupdate -d -k $CONFBASE:key.example.net. 444 } | nsupdate -d -k $CONFBASE:key.example.net.
243 445
446=item node-change = relative-or-absolute-path
447
448Same as C<node-change>, but gets called whenever something about a
449connection changes (such as the source IP address).
450
244=item node-down = relative-or-absolute-path 451=item node-down = relative-or-absolute-path
245 452
246Same as C<node-up>, but gets called whenever a connection is lost. 453Same as C<node-up>, but gets called whenever a connection is lost.
247 454
248=item http-proxy-host = hostname/ip
249
250The C<http-proxy-*> family of options are only available if gvpe was
251compiled with the C<--enable-http-proxy> option and enable tunneling of
252tcp connections through a http proxy server.
253
254C<http-proxy-host> and C<http-proxy-port> should specify the hostname and
255port number of the proxy server. See C<http-proxy-loginpw> if your proxy
256requires authentication.
257
258Please note that gvpe will still try to resolve all hostnames in the
259configuration file, so if you are behind a proxy without access to a dns
260server better use numerical IP addresses.
261
262To make best use of this option disable all protocols except tcp in your
263config file and make sure your routers (or all other hosts) are listening
264on a port that the proxy allows (443, https, is a common choice).
265
266If you have a router, connecting to it will suffice. Otherwise tcp must be
267enabled on all hosts.
268
269Example:
270
271 http-proxy-host = proxy.example.com
272 http-proxy-port = 3128 # 8080 is another common choice
273 http-proxy-auth = schmorp:grumbeere
274
275=item http-proxy-port = proxy-tcp-port
276
277The port where your proxy server listens.
278
279=item http-proxy-auth = login:password
280
281The optional login and password used to authenticate to the proxy server,
282seperated by a literal colon (C<:>). Only basic authentication is
283currently supported.
284
285=item pid-file = path 455=item pid-file = path
286 456
287The path to the pid file to check and create (Default: 457The path to the pid file to check and create
458(default: C<LOCALSTATEDIR/run/gvpe.pid>). The first C<%s> is replaced by
459the nodename - any other use of C<%> must be written as C<%%>.
460
461=item private-key = relative-path-to-key
462
463Sets the path (relative to the config directory) to the private key
464(default: C<hostkey>). This is a printf format string so every C<%> must
465be doubled. A single C<%s> is replaced by the hostname, so you could
466use paths like C<hostkeys/%s> to fetch the files at the location where
467C<gvpectrl> puts them.
468
469Since only the private key file of the current node is used and the
470private key file should be kept secret per-node to avoid spoofing, it is
471not recommended to use this feature.
472
473=item rekey = seconds
474
475Sets the rekeying interval in seconds (default: C<3607>). Connections are
476reestablished every C<rekey> seconds, making them use a new encryption
477key.
478
479=item seed-device = path
480
481The random device used to initially and regularly seed the random
482number generator (default: F</dev/urandom>). Randomness is of paramount
483importance to the security of the algorithms used in gvpe.
484
485On program start and every seed-interval, gvpe will read 64 octets.
486
487Setting this path to the empty string will disable this functionality
488completely (the underlying crypto library will likely look for entropy
489sources on it's own though, so not all is lost).
490
491=item seed-interval = seconds
492
493The number of seconds between reseeds of the random number generator
494(default: C<3613>). A value of C<0> disables this regular reseeding.
288 495
289=back 496=back
290 497
291=head2 NODE SPECIFIC SETTINGS 498=head2 NODE SPECIFIC SETTINGS
292 499
293The following settings are node-specific, that is, every node can have 500The following settings are node-specific, that is, every node can have
294different settings, even within the same gvpe instance. Settings that are 501different settings, even within the same gvpe instance. Settings that are
295executed before the first node section set the defaults, settings that are 502set before the first node section set the defaults, settings that are
296executed within a node section only apply to the given node. 503set within a node section only apply to the given node.
297 504
298=over 4 505=over 4
299 506
507=item allow-direct = nodename
508
509Allow direct connections to this node. See C<deny-direct> for more info.
510
511=item compress = yes|true|on | no|false|off
512
513For the current node, this specified whether it will accept compressed
514packets, and for all other nodes, this specifies whether to try to
515compress data packets sent to this node (default: C<yes>). Compression is
516really cheap even on slow computers, has no size overhead at all and will
517only be used when the other side supports compression, so enabling this is
518often a good idea.
519
520=item connect = ondemand | never | always | disabled
521
522Sets the connect mode (default: C<always>). It can be C<always> (always
523try to establish and keep a connection to the given node), C<never>
524(never initiate a connection to the given host, but accept connections),
525C<ondemand> (try to establish a connection when there are outstanding
526packets in the queue and take it down after the keepalive interval) or
527C<disabled> (node is bad, don't talk to it).
528
529Routers will automatically be forced to C<always> unless they are
530C<disabled>, to ensure all nodes can talk to each other.
531
532=item deny-direct = nodename | *
533
534Deny direct connections to the specified node (or all nodes when C<*>
535is given). Only one node can be specified, but you can use multiple
536C<allow-direct> and C<deny-direct> statements. This only makes sense in
537networks with routers, as routers are required for indirect connections.
538
539Sometimes, a node cannot reach some other nodes for reasons of network
540connectivity. For example, a node behind a firewall that only allows
541connections to/from a single other node in the network. In this case one
542should specify C<deny-direct = *> and C<allow-direct = othernodename> (the other
543node I<must> be a router for this to work).
544
545The algorithm to check whether a connection may be direct is as follows:
546
5471. Other node mentioned in an C<allow-direct>? If yes, allow the connection.
548
5492. Other node mentioned in a C<deny-direct>? If yes, deny direct connections.
550
5513. Allow the connection.
552
553That is, C<allow-direct> takes precedence over C<deny-direct>.
554
555The check is done in both directions, i.e. both nodes must allow a direct
556connection before one is attempted, so you only need to specify connect
557limitations on one node.
558
559=item dns-domain = domain-suffix
560
561The DNS domain suffix that points to the DNS tunnel server for this node.
562
563The domain must point to a NS record that points to the I<dns-hostname>,
564i.e.
565
566 dns-domainname = tunnel.example.net
567 dns-hostname = tunnel-server.example.net
568
569Corresponds to the following DNS entries in the C<example.net> domain:
570
571 tunnel.example.net. NS tunnel-server.example.net.
572 tunnel-server.example.net. A 13.13.13.13
573
574=item dns-hostname = hostname/ip
575
576The address to bind the DNS tunnel socket to, similar to the C<hostname>,
577but for the DNS tunnel protocol only. Default: C<0.0.0.0>, but that might
578change.
579
300=item udp-port = port-number 580=item dns-port = port-number
301 581
302Sets the port number used by the UDP protocol (default: C<655>, not 582The port to bind the DNS tunnel socket to. Must be C<53> on DNS tunnel servers.
303officially assigned by IANA!).
304 583
305=item tcp-port = port-number 584=item enable-dns = yes|true|on | no|false|off
306 585
307Similar to C<udp-port> (default: C<655>), but sets the TCP port number. 586See gvpe.protocol(7) for a description of the DNS transport
587protocol. Avoid this protocol if you can.
588
589Enable the DNS tunneling protocol on this node, either as server or as
590client. Support for this transport protocol is only available when gvpe
591was compiled using the C<--enable-dns> option.
592
593=item enable-icmp = yes|true|on | no|false|off
594
595See gvpe.protocol(7) for a description of the ICMP transport protocol.
596
597Enable the ICMP transport using ICMP packets of type C<icmp-type> on this
598node.
308 599
309=item enable-rawip = yes|true|on | no|false|off 600=item enable-rawip = yes|true|on | no|false|off
310 601
602See gvpe.protocol(7) for a description of the RAW IP transport protocol.
603
311Enable the RAW IPv4 transport using the C<ip-proto> protocol 604Enable the RAW IPv4 transport using the C<ip-proto> protocol
312(default: C<no>). This is the best choice, since the overhead per packet 605(default: C<no>).
313is only 38 bytes, as opposed to UDP's 58 (or TCP's 60+). 606
607=item enable-tcp = yes|true|on | no|false|off
608
609See gvpe.protocol(7) for a description of the TCP transport protocol.
610
611Enable the TCPv4 transport using the C<tcp-port> port
612(default: C<no>). Support for this transport protocol is only available
613when gvpe was compiled using the C<--enable-tcp> option.
314 614
315=item enable-udp = yes|true|on | no|false|off 615=item enable-udp = yes|true|on | no|false|off
316 616
617See gvpe.protocol(7) for a description of the UDP transport protocol.
618
317Enable the UDPv4 transport using the C<udp-port> port (default: C<yes>, 619Enable the UDPv4 transport using the C<udp-port> port (default: C<no>).
318but this will change!). This is a good general choice since UDP tunnels
319well through many firewalls.
320 620
321NOTE: Please specify C<enable-udp = yes> even though it is the default, as 621=item hostname = hostname | ip [can not be defaulted]
322some future version will have all protocols disabled by default.
323 622
324=item enable-tcp = yes|true|on | no|false|off 623Forces the address of this node to be set to the given DNS hostname or IP
624address. It will be resolved before each connect request, so dyndns should
625work fine. If this setting is not specified and a router is available,
626then the router will be queried for the address of this node. Otherwise,
627the connection attempt will fail.
325 628
326Enable the TCPv4 transport using the C<tcp-port> port 629Note that DNS resolving is done synchronously, pausing the daemon. If that
327(default: C<no>). Support for this horribly unsuitable protocol is only 630is an issue you need to specify IP addresses.
328available when gvpe was compiled using the C<--enable-tcp> option. Never
329use this transport unless you really must, it is horribly ineffiecent and
330resource-intensive compared to the other transports.
331 631
332=item router-priority = positive-number 632=item icmp-type = integer
333 633
334Sets the router priority of the given host (default: C<0>, disabled). If 634Sets the type value to be used for outgoing (and incoming) packets sent
335some host tries to connect to another host without a hostname, it asks 635via the ICMP transport.
336the router host for it's IP address. The router host is the one with the
337highest priority that is currently reachable. Make sure all clients always
338connect to the router hosts, otherwise conencting to them is impossible.
339 636
340=item connect = ondemand|never|always|disabled 637The default is C<0> (which is C<echo-reply>, also known as
638"ping-reply"). Other useful values include C<8> (C<echo-request>, a.k.a.
639"ping") and C<11> (C<time-exceeded>), but any 8-bit value can be used.
341 640
342Sets the connect mode (default: C<always>). It can be C<always> (always 641=item if-up-data = value
343try to establish and keep a conenction to the given host), C<never> 642
344(nevr initiate a connection to the given host, but accept connections), 643The value specified using this directive will be passed to the C<if-up>
345C<ondemand> (try to establish a connection on the first packet sent, and 644script in the environment variable C<IFUPDATA>.
346take it down after the keepalive interval) or C<disabled> (node is bad,
347don't talk to it).
348 645
349=item inherit-tos = yes|true|on | no|false|off 646=item inherit-tos = yes|true|on | no|false|off
350 647
351Wether to inherit the TOS settings of packets sent to the tunnel when 648Whether to inherit the TOS settings of packets sent to the tunnel when
352sending packets to this node (default: C<yes>). If set to C<yes> then 649sending packets to this node (default: C<yes>). If set to C<yes> then
353outgoing tunnel packets will have the same TOS setting as the packets sent 650outgoing tunnel packets will have the same TOS setting as the packets sent
354to the tunnel device, which is usually what you want. 651to the tunnel device, which is usually what you want.
355 652
356=item compress = yes|true|on | no|false|off
357
358Wether to compress data packets sent to this host (default: C<yes>).
359Compression is really cheap even on slow computers and has no size
360overhead at all, so enabling this is a good idea.
361
362=item max-retry = positive-number 653=item max-retry = positive-number
363 654
364The maximum interval in seconds (default: C<28800>, 8 hours) between 655The maximum interval in seconds (default: C<3600>, one hour) between
365retries to establish a connection to this node. When a connection cannot 656retries to establish a connection to this node. When a connection cannot
366be established, gvpe uses exponential backoff capped at this value. It's 657be established, gvpe uses exponential back-off capped at this value. It's
367sometimes useful to set this to a much lower value (e.g. C<120>) on 658sometimes useful to set this to a much lower value (e.g. C<120>) on
368connections to routers that usually are stable but sometimes are down, to 659connections to routers that usually are stable but sometimes are down, to
369assure quick reconnections. 660assure quick reconnections even after longer downtimes.
661
662=item max-ttl = seconds
663
664Expire packets that couldn't be sent after this many seconds
665(default: C<60>). Gvpe will normally queue packets for a node without an
666active connection, in the hope of establishing a connection soon. This
667value specifies the maximum lifetime a packet will stay in the queue, if a
668packet gets older, it will be thrown away.
669
670=item max-queue = positive-number>=1
671
672The maximum number of packets that will be queued (default: C<512>)
673for this node. If more packets are sent then earlier packets will be
674expired. See C<max-ttl>, above.
675
676=item router-priority = 0 | 1 | positive-number>=2
677
678Sets the router priority of the given node (default: C<0>, disabled).
679
680If some node tries to connect to another node but it doesn't have a
681hostname, it asks a router node for it's IP address. The router node
682chosen is the one with the highest priority larger than C<1> that is
683currently reachable. This is called a I<mediated> connection, as the
684connection itself will still be direct, but it uses another node to
685mediate between the two nodes.
686
687The value C<0> disables routing, that means if the node receives a packet
688not for itself it will not forward it but instead drop it.
689
690The special value C<1> allows other hosts to route through the router
691host, but they will never route through it by default (i.e. the config
692file of another node needs to specify a router priority higher than one
693to choose such a node for routing).
694
695The idea behind this is that some hosts can, if required, bump the
696C<router-priority> setting to higher than C<1> in their local config to
697route through specific hosts. If C<router-priority> is C<0>, then routing
698will be refused, so C<1> serves as a "enable, but do not use by default"
699switch.
700
701Nodes with C<router-priority> set to C<2> or higher will always be forced
702to C<connect> = C<always> (unless they are C<disabled>).
703
704=item tcp-port = port-number
705
706Similar to C<udp-port> (default: C<655>), but sets the TCP port number.
707
708=item udp-port = port-number
709
710Sets the port number used by the UDP protocol (default: C<655>, not
711officially assigned by IANA!).
370 712
371=back 713=back
372 714
373=head1 CONFIG DIRECTORY LAYOUT 715=head1 CONFIG DIRECTORY LAYOUT
374 716
388 730
389If used the node up or node-down scripts. 731If used the node up or node-down scripts.
390 732
391=item hostkey 733=item hostkey
392 734
393The private key (taken from C<hostkeys/nodename>) of the current host. 735The (default path of the) private key of the current host.
394 736
395=item pubkey/nodename 737=item pubkey/nodename
396 738
397The public keys of the other nodes, one file per node. 739The public keys of the other nodes, one file per node.
398 740
402 744
403gvpe(5), gvpe(8), gvpectrl(8). 745gvpe(5), gvpe(8), gvpectrl(8).
404 746
405=head1 AUTHOR 747=head1 AUTHOR
406 748
407Marc Lehmann <gvpe@plan9.de> 749Marc Lehmann <gvpe@schmorp.de>
408 750

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