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Revision: 1.38
Committed: Thu Oct 25 03:13:13 2018 UTC (5 years, 6 months ago) by root
Branch: MAIN
CVS Tags: HEAD
Changes since 1.37: +3 -3 lines
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# Content
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133 .\" ========================================================================
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135 .IX Title "GVPE.CONF 5"
136 .TH GVPE.CONF 5 "2016-11-12" "3.0" "GNU Virtual Private Ethernet"
137 .\" For nroff, turn off justification. Always turn off hyphenation; it makes
138 .\" way too many mistakes in technical documents.
139 .if n .ad l
140 .nh
141 .SH "NAME"
142 gvpe.conf \- configuration file for the GNU VPE daemon
143 .SH "SYNOPSIS"
144 .IX Header "SYNOPSIS"
145 .Vb 4
146 \& # global options for all nodes
147 \& udp\-port = 407
148 \& mtu = 1492
149 \& ifname = vpn0
150 \&
151 \& # first node is named branch1 and is at 1.2.3.4
152 \& node = branch1
153 \& hostname = 1.2.3.4
154 \&
155 \& # second node uses dns to resolve the address
156 \& node = branch2
157 \& hostname = www.example.net
158 \& udp\-port = 500 # this host uses a different udp\-port
159 \&
160 \& # third node has no fixed ip address
161 \& node = branch3
162 \& connect = ondemand
163 .Ve
164 .SH "DESCRIPTION"
165 .IX Header "DESCRIPTION"
166 The gvpe config file consists of a series of lines that contain \f(CW\*(C`variable
167 = value\*(C'\fR pairs. Empty lines are ignored. Comments start with a \f(CW\*(C`#\*(C'\fR and
168 extend to the end of the line. They can be used on their own lines, or
169 after any directives. Whitespace is allowed around the \f(CW\*(C`=\*(C'\fR sign or after
170 values, but not within the variable names or values themselves.
171 .PP
172 All settings are applied \*(L"in order\*(R", that is, later settings of the same
173 variable overwrite earlier ones.
174 .PP
175 The only exceptions to the above are the following directives:
176 .IP "node nodename" 4
177 .IX Item "node nodename"
178 Introduces a node section. The nodename is used to select the right
179 configuration section and is the same string as is passed as an argument
180 to the gvpe daemon.
181 .Sp
182 Multiple \f(CW\*(C`node\*(C'\fR statements with the same node name are supported and will
183 be merged together.
184 .IP "global" 4
185 .IX Item "global"
186 This statement switches back to the global section, which is mainly
187 useful if you want to include a second config file, e..g for local
188 customisations. To do that, simply include this at the very end of your
189 config file:
190 .Sp
191 .Vb 2
192 \& global
193 \& include local.conf
194 .Ve
195 .IP "on nodename ..." 4
196 .IX Item "on nodename ..."
197 .PD 0
198 .IP "on !nodename ..." 4
199 .IX Item "on !nodename ..."
200 .PD
201 You can prefix any configuration directive with \f(CW\*(C`on\*(C'\fR and a nodename. \s-1GVPE\s0
202 will will only \*(L"execute\*(R" it on the named node, or (if the nodename starts
203 with \f(CW\*(C`!\*(C'\fR) on all nodes except the named one.
204 .Sp
205 Example: set the \s-1MTU\s0 to \f(CW1450\fR everywhere, \f(CW\*(C`loglevel\*(C'\fR to \f(CW\*(C`noise\*(C'\fR on
206 \&\f(CW\*(C`branch1\*(C'\fR, and \f(CW\*(C`connect\*(C'\fR to \f(CW\*(C`ondemand\*(C'\fR everywhere but on branch2.
207 .Sp
208 .Vb 3
209 \& mtu = 1450
210 \& on branch1 loglevel = noise
211 \& on !branch2 connect = ondemand
212 .Ve
213 .IP "include relative-or-absolute-path" 4
214 .IX Item "include relative-or-absolute-path"
215 Reads the specified file (the path must not contain whitespace or \f(CW\*(C`=\*(C'\fR
216 characters) and evaluate all config directives in it as if they were
217 spelled out in place of the \f(CW\*(C`include\*(C'\fR directive.
218 .Sp
219 The path is a printf format string, that is, you must escape any \f(CW\*(C`%\*(C'\fR
220 by doubling it, and you can have a single \f(CW%s\fR inside, which will be
221 replaced by the current nodename.
222 .Sp
223 Relative paths are interpreted relative to the \s-1GVPE\s0 config directory.
224 .Sp
225 Example: include the file \fIlocal.conf\fR in the config directory on every
226 node.
227 .Sp
228 .Vb 1
229 \& include local.conf
230 .Ve
231 .Sp
232 Example: include a file \fIconf/\fRnodename\fI.conf\fR
233 .Sp
234 .Vb 1
235 \& include conf/%s.conf
236 .Ve
237 .SH "ANATOMY OF A CONFIG FILE"
238 .IX Header "ANATOMY OF A CONFIG FILE"
239 Usually, a config file starts with a few global settings (like the \s-1UDP\s0
240 port to listen on), followed by node-specific sections that begin with a
241 \&\f(CW\*(C`node = nickname\*(C'\fR line.
242 .PP
243 Every node that is part of the network must have a section that starts
244 with \f(CW\*(C`node = nickname\*(C'\fR. The number and order of the nodes is important
245 and must be the same on all nodes. It is not uncommon for node sections to
246 be completely empty \- if the default values are right.
247 .PP
248 Node-specific settings can be used at any time. If used before the first
249 node section they will set the default values for all following nodes.
250 .SH "CONFIG VARIABLES"
251 .IX Header "CONFIG VARIABLES"
252 .SS "\s-1GLOBAL SETTINGS\s0"
253 .IX Subsection "GLOBAL SETTINGS"
254 Global settings will affect the behaviour of the running gvpe daemon, that
255 is, they are in some sense node-specific (config files can set different
256 values on different nodes using \f(CW\*(C`on\*(C'\fR), but will affect the behaviour of
257 the gvpe daemon and all connections it creates.
258 .IP "chroot = path or /" 4
259 .IX Item "chroot = path or /"
260 Tells \s-1GVPE\s0 to \fIchroot\fR\|(2) to the specified path after reading all necessary
261 files, binding to sockets and running the \f(CW\*(C`if\-up\*(C'\fR script, but before
262 running \f(CW\*(C`node\-up\*(C'\fR or any other scripts.
263 .Sp
264 The special path \fI/\fR instructs \s-1GVPE\s0 to create (and remove) an empty
265 temporary directory to use as new root. This is most secure, but makes it
266 impossible to use any scripts other than the \f(CW\*(C`if\-up\*(C'\fR one.
267 .IP "chuid = numerical-uid" 4
268 .IX Item "chuid = numerical-uid"
269 .PD 0
270 .IP "chgid = numerical-gid" 4
271 .IX Item "chgid = numerical-gid"
272 .PD
273 These two options tell \s-1GVPE\s0 to change to the given user and/or group id
274 after reading all necessary files, binding to sockets and running the
275 \&\f(CW\*(C`if\-up\*(C'\fR script.
276 .Sp
277 Other scripts, such as \f(CW\*(C`node\-up\*(C'\fR, are run with the new user id or group id.
278 .IP "chuser = username" 4
279 .IX Item "chuser = username"
280 Alternative to \f(CW\*(C`chuid\*(C'\fR and \f(CW\*(C`chgid\*(C'\fR: Sets both \f(CW\*(C`chuid\*(C'\fR and \f(CW\*(C`chgid\*(C'\fR
281 to the user and (primary) group ids of the specified user (for example,
282 \&\f(CW\*(C`nobody\*(C'\fR).
283 .IP "dns-forw-host = hostname/ip" 4
284 .IX Item "dns-forw-host = hostname/ip"
285 The \s-1DNS\s0 server to forward \s-1DNS\s0 requests to for the \s-1DNS\s0 tunnel protocol
286 (default: \f(CW127.0.0.1\fR, changing it is highly recommended).
287 .IP "dns-forw-port = port-number" 4
288 .IX Item "dns-forw-port = port-number"
289 The port where the \f(CW\*(C`dns\-forw\-host\*(C'\fR is to be contacted (default: \f(CW53\fR,
290 which is fine in most cases).
291 .IP "dns-case-preserving = yes|true|on | no|false|off" 4
292 .IX Item "dns-case-preserving = yes|true|on | no|false|off"
293 Sets whether the \s-1DNS\s0 transport forwarding server preserves case (\s-1DNS\s0
294 servers have to, but some access systems are even more broken than others)
295 (default: true).
296 .Sp
297 Normally, when the forwarding server changes the case of domain names then
298 \&\s-1GVPE\s0 will automatically set this to false.
299 .IP "dns-max-outstanding = integer-number-of-requests" 4
300 .IX Item "dns-max-outstanding = integer-number-of-requests"
301 The maximum number of outstanding \s-1DNS\s0 transport requests
302 (default: \f(CW100\fR). \s-1GVPE\s0 will never issue more requests then the given
303 limit without receiving replies. In heavily overloaded situations it might
304 help to set this to a low number (e.g. \f(CW3\fR or even \f(CW1\fR) to limit the
305 number of parallel requests.
306 .Sp
307 The default should be working \s-1OK\s0 for most links.
308 .IP "dns-overlap-factor = float" 4
309 .IX Item "dns-overlap-factor = float"
310 The \s-1DNS\s0 transport uses the minimum request latency (\fBmin_latency\fR) seen
311 during a connection as it's timing base. This factor (default: \f(CW0.5\fR,
312 must be > 0) is multiplied by \fBmin_latency\fR to get the maximum sending
313 rate (= minimum send interval), i.e. a factor of \f(CW1\fR means that a new
314 request might be generated every \fBmin_latency\fR seconds, which means on
315 average there should only ever be one outstanding request. A factor of
316 \&\f(CW0.5\fR means that \s-1GVPE\s0 will send requests twice as often as the minimum
317 latency measured.
318 .Sp
319 For congested or picky \s-1DNS\s0 forwarders you could use a value nearer to or
320 exceeding \f(CW1\fR.
321 .Sp
322 The default should be working \s-1OK\s0 for most links.
323 .IP "dns-send-interval = send-interval-in-seconds" 4
324 .IX Item "dns-send-interval = send-interval-in-seconds"
325 The minimum send interval (= maximum rate) that the \s-1DNS\s0 transport will
326 use to send new \s-1DNS\s0 requests. \s-1GVPE\s0 will not exceed this rate even when
327 the latency is very low. The default is \f(CW0.01\fR, which means \s-1GVPE\s0 will
328 not send more than 100 \s-1DNS\s0 requests per connection per second. For
329 high-bandwidth links you could go lower, e.g. to \f(CW0.001\fR or so. For
330 congested or rate-limited links, you might want to go higher, say \f(CW0.1\fR,
331 \&\f(CW0.2\fR or even higher.
332 .Sp
333 The default should be working \s-1OK\s0 for most links.
334 .IP "dns-timeout-factor = float" 4
335 .IX Item "dns-timeout-factor = float"
336 Factor to multiply the \f(CW\*(C`min_latency\*(C'\fR (see \f(CW\*(C`dns\-overlap\-factor\*(C'\fR) by to
337 get request timeouts. The default of \f(CW8\fR means that the \s-1DNS\s0 transport
338 will resend the request when no reply has been received for longer than
339 eight times the minimum (= expected) latency, assuming the request or
340 reply has been lost.
341 .Sp
342 For congested links a higher value might be necessary (e.g. \f(CW30\fR). If
343 the link is very stable lower values (e.g. \f(CW2\fR) might work
344 nicely. Values near or below \f(CW1\fR makes no sense whatsoever.
345 .Sp
346 The default should be working \s-1OK\s0 for most links but will result in low
347 throughput if packet loss is high.
348 .IP "if-up = relative-or-absolute-path" 4
349 .IX Item "if-up = relative-or-absolute-path"
350 Sets the path of a script that should be called immediately after the
351 network interface is initialized (but not necessarily up). The following
352 environment variables are passed to it (the values are just examples).
353 .Sp
354 Variables that have the same value on all nodes:
355 .RS 4
356 .IP "CONFBASE=/etc/gvpe" 4
357 .IX Item "CONFBASE=/etc/gvpe"
358 The configuration base directory.
359 .IP "IFNAME=vpn0" 4
360 .IX Item "IFNAME=vpn0"
361 The network interface to initialize.
362 .IP "IFTYPE=native # or tincd" 4
363 .IX Item "IFTYPE=native # or tincd"
364 .PD 0
365 .IP "IFSUBTYPE=linux # or freebsd, darwin etc.." 4
366 .IX Item "IFSUBTYPE=linux # or freebsd, darwin etc.."
367 .PD
368 The interface type (\f(CW\*(C`native\*(C'\fR or \f(CW\*(C`tincd\*(C'\fR) and the subtype (usually the
369 \&\s-1OS\s0 name in lowercase) that this \s-1GVPE\s0 was configured for. Can be used to
370 select the correct syntax to use for network-related commands.
371 .IP "MTU=1436" 4
372 .IX Item "MTU=1436"
373 The \s-1MTU\s0 to set the interface to. You can use lower values (if done
374 consistently on all nodes), but this is usually either inefficient or
375 simply ineffective.
376 .IP "NODES=5" 4
377 .IX Item "NODES=5"
378 The number of nodes in this \s-1GVPE\s0 network.
379 .RE
380 .RS 4
381 .Sp
382 Variables that are node-specific and with values pertaining to the node
383 running this \s-1GVPE:\s0
384 .IP "IFUPDATA=string" 4
385 .IX Item "IFUPDATA=string"
386 The value of the configuration directive \f(CW\*(C`if\-up\-data\*(C'\fR.
387 .IP "MAC=fe:fd:80:00:00:01" 4
388 .IX Item "MAC=fe:fd:80:00:00:01"
389 The \s-1MAC\s0 address the network interface has to use.
390 .Sp
391 Might be used to initialize interfaces on platforms where \s-1GVPE\s0 does not
392 do this automatically. Please see the \f(CW\*(C`gvpe.osdep(5)\*(C'\fR man page for
393 platform-specific information.
394 .IP "NODENAME=branch1" 4
395 .IX Item "NODENAME=branch1"
396 The nickname of the node.
397 .IP "NODEID=1" 4
398 .IX Item "NODEID=1"
399 The numerical node \s-1ID\s0 of the node running this instance of \s-1GVPE.\s0 The first
400 node mentioned in the config file gets \s-1ID 1,\s0 the second \s-1ID 2\s0 and so on.
401 .RE
402 .RS 4
403 .Sp
404 In addition, all node-specific variables (except \f(CW\*(C`NODEID\*(C'\fR) will be
405 available with a postfix of \f(CW\*(C`_nodeid\*(C'\fR, which contains the value for that
406 node, e.g. the \f(CW\*(C`MAC_1\*(C'\fR variable contains the \s-1MAC\s0 address of node #1, while
407 the \f(CW\*(C`NODENAME_22\*(C'\fR variable contains the name of node #22.
408 .Sp
409 Here is a simple if-up script:
410 .Sp
411 .Vb 5
412 \& #!/bin/sh
413 \& ip link set $IFNAME up
414 \& [ $NODENAME = branch1 ] && ip addr add 10.0.0.1 dev $IFNAME
415 \& [ $NODENAME = branch2 ] && ip addr add 10.1.0.1 dev $IFNAME
416 \& ip route add 10.0.0.0/8 dev $IFNAME
417 .Ve
418 .Sp
419 More complicated examples (using routing to reduce \s-1ARP\s0 traffic) can be
420 found in the \fIetc/\fR subdirectory of the distribution.
421 .RE
422 .IP "ifname = devname" 4
423 .IX Item "ifname = devname"
424 Sets the tun interface name to the given name. The default is OS-specific
425 and most probably something like \f(CW\*(C`tun0\*(C'\fR.
426 .IP "ifpersist = yes|true|on | no|false|off" 4
427 .IX Item "ifpersist = yes|true|on | no|false|off"
428 Should the tun/tap device be made persistent, that is, should the device
429 stay up even when gvpe exits? Some versions of the tunnel device have
430 problems sending packets when gvpe is restarted in persistent mode, so
431 if the connections can be established but you cannot send packets from
432 the local node, try to set this to \f(CW\*(C`off\*(C'\fR and do an ifconfig down on the
433 device.
434 .IP "ip-proto = numerical-ip-protocol" 4
435 .IX Item "ip-proto = numerical-ip-protocol"
436 Sets the protocol number to be used for the rawip protocol. This is a
437 global option because all nodes must use the same protocol, and since
438 there are no port numbers, you cannot easily run more than one gvpe
439 instance using the same protocol, nor can you share the protocol with
440 other programs.
441 .Sp
442 The default is 47 (\s-1GRE\s0), which has a good chance of tunneling
443 through firewalls (but note that gvpe's rawip protocol is not \s-1GRE\s0
444 compatible). Other common choices are 50 (\s-1IPSEC, ESP\s0), 51 (\s-1IPSEC, AH\s0), 4
445 (\s-1IPIP\s0 tunnels) or 98 (\s-1ENCAP,\s0 rfc1241).
446 .Sp
447 Many versions of Linux seem to have a bug that causes them to reorder
448 packets for some ip protocols (\s-1GRE, ESP\s0) but not for others (\s-1AH\s0), so
449 choose wisely (that is, use 51, \s-1AH\s0).
450 .IP "http-proxy-host = hostname/ip" 4
451 .IX Item "http-proxy-host = hostname/ip"
452 The \f(CW\*(C`http\-proxy\-*\*(C'\fR family of options are only available if gvpe was
453 compiled with the \f(CW\*(C`\-\-enable\-http\-proxy\*(C'\fR option and enable tunneling of
454 tcp connections through a http proxy server.
455 .Sp
456 \&\f(CW\*(C`http\-proxy\-host\*(C'\fR and \f(CW\*(C`http\-proxy\-port\*(C'\fR should specify the hostname and
457 port number of the proxy server. See \f(CW\*(C`http\-proxy\-loginpw\*(C'\fR if your proxy
458 requires authentication.
459 .Sp
460 Please note that gvpe will still try to resolve all hostnames in the
461 configuration file, so if you are behind a proxy without access to a \s-1DNS\s0
462 server better use numerical \s-1IP\s0 addresses.
463 .Sp
464 To make best use of this option disable all protocols except \s-1TCP\s0 in your
465 config file and make sure your routers (or all other nodes) are listening
466 on a port that the proxy allows (443, https, is a common choice).
467 .Sp
468 If you have a router, connecting to it will suffice. Otherwise \s-1TCP\s0 must be
469 enabled on all nodes.
470 .Sp
471 Example:
472 .Sp
473 .Vb 3
474 \& http\-proxy\-host = proxy.example.com
475 \& http\-proxy\-port = 3128 # 8080 is another common choice
476 \& http\-proxy\-auth = schmorp:grumbeere
477 .Ve
478 .IP "http-proxy-port = proxy-tcp-port" 4
479 .IX Item "http-proxy-port = proxy-tcp-port"
480 The port where your proxy server listens.
481 .IP "http-proxy-auth = login:password" 4
482 .IX Item "http-proxy-auth = login:password"
483 The optional login and password used to authenticate to the proxy server,
484 separated by a literal colon (\f(CW\*(C`:\*(C'\fR). Only basic authentication is
485 currently supported.
486 .IP "keepalive = seconds" 4
487 .IX Item "keepalive = seconds"
488 Sets the keepalive probe interval in seconds (default: \f(CW60\fR). After this
489 many seconds of inactivity the daemon will start to send keepalive probe
490 every 3 seconds until it receives a reply from the other end. If no reply
491 is received within 15 seconds, the peer is considered unreachable and the
492 connection is closed.
493 .IP "loglevel = noise|trace|debug|info|notice|warn|error|critical" 4
494 .IX Item "loglevel = noise|trace|debug|info|notice|warn|error|critical"
495 Set the logging level. Connection established messages are logged at level
496 \&\f(CW\*(C`info\*(C'\fR, notable errors are logged with \f(CW\*(C`error\*(C'\fR. Default is \f(CW\*(C`info\*(C'\fR.
497 .IP "mtu = bytes" 4
498 .IX Item "mtu = bytes"
499 Sets the maximum \s-1MTU\s0 that should be used on outgoing packets (basically
500 the \s-1MTU\s0 of the outgoing interface) The daemon will automatically calculate
501 maximum overhead (e.g. \s-1UDP\s0 header size, encryption blocksize...) and pass
502 this information to the \f(CW\*(C`if\-up\*(C'\fR script.
503 .Sp
504 Recommended values are 1500 (ethernet), 1492 (pppoe), 1472 (pptp).
505 .Sp
506 This value must be the minimum of the \s-1MTU\s0 values of all nodes.
507 .IP "nfmark = integer" 4
508 .IX Item "nfmark = integer"
509 This advanced option, when set to a nonzero value (default: \f(CW0\fR), tries
510 to set the netfilter mark (or fwmark) value on all sockets gvpe uses to
511 send packets.
512 .Sp
513 This can be used to make gvpe use a different set of routing rules. For
514 example, on GNU/Linux, the \f(CW\*(C`if\-up\*(C'\fR could set \f(CW\*(C`nfmark\*(C'\fR to 1000 and then
515 put all routing rules into table \f(CW99\fR and then use an ip rule to make
516 gvpe traffic avoid that routing table, in effect routing normal traffic
517 via gvpe and gvpe traffic via the normal system routing tables:
518 .Sp
519 .Vb 1
520 \& ip rule add not fwmark 1000 lookup 99
521 .Ve
522 .IP "node-up = relative-or-absolute-path" 4
523 .IX Item "node-up = relative-or-absolute-path"
524 Sets a command (default: none) that should be called whenever a connection
525 is established (even on rekeying operations). Note that node\-up/down
526 scripts will be run asynchronously, but execution is serialised, so there
527 will only ever be one such script running.
528 .Sp
529 In addition to all the variables passed to \f(CW\*(C`if\-up\*(C'\fR scripts, the following
530 environment variables will be set (values are just examples):
531 .RS 4
532 .IP "DESTNODE=branch2" 4
533 .IX Item "DESTNODE=branch2"
534 The name of the remote node.
535 .IP "DESTID=2" 4
536 .IX Item "DESTID=2"
537 The node id of the remote node.
538 .IP "DESTSI=rawip/88.99.77.55:0" 4
539 .IX Item "DESTSI=rawip/88.99.77.55:0"
540 The \*(L"socket info\*(R" of the target node, protocol dependent but usually in
541 the format protocol/ip:port.
542 .IP "DESTIP=188.13.66.8" 4
543 .IX Item "DESTIP=188.13.66.8"
544 The numerical \s-1IP\s0 address of the remote node (gvpe accepts connections from
545 everywhere, as long as the other node can authenticate itself).
546 .IP "DESTPORT=655 # deprecated" 4
547 .IX Item "DESTPORT=655 # deprecated"
548 The protocol port used by the other side, if applicable.
549 .IP "STATE=up" 4
550 .IX Item "STATE=up"
551 Node-up scripts get called with STATE=up, node-change scripts get called
552 with STATE=change and node-down scripts get called with STATE=down.
553 .RE
554 .RS 4
555 .Sp
556 Here is a nontrivial example that uses nsupdate to update the name => ip
557 mapping in some \s-1DNS\s0 zone:
558 .Sp
559 .Vb 6
560 \& #!/bin/sh
561 \& {
562 \& echo update delete $DESTNODE.lowttl.example.net. a
563 \& echo update add $DESTNODE.lowttl.example.net. 1 in a $DESTIP
564 \& echo
565 \& } | nsupdate \-d \-k $CONFBASE:key.example.net.
566 .Ve
567 .RE
568 .IP "node-change = relative-or-absolute-path" 4
569 .IX Item "node-change = relative-or-absolute-path"
570 Same as \f(CW\*(C`node\-change\*(C'\fR, but gets called whenever something about a
571 connection changes (such as the source \s-1IP\s0 address).
572 .IP "node-down = relative-or-absolute-path" 4
573 .IX Item "node-down = relative-or-absolute-path"
574 Same as \f(CW\*(C`node\-up\*(C'\fR, but gets called whenever a connection is lost.
575 .IP "pid-file = path" 4
576 .IX Item "pid-file = path"
577 The path to the pid file to check and create
578 (default: \f(CW\*(C`LOCALSTATEDIR/run/gvpe.pid\*(C'\fR). The first \f(CW%s\fR is replaced by
579 the nodename \- any other use of \f(CW\*(C`%\*(C'\fR must be written as \f(CW\*(C`%%\*(C'\fR.
580 .IP "private-key = relative-path-to-key" 4
581 .IX Item "private-key = relative-path-to-key"
582 Sets the path (relative to the config directory) to the private key
583 (default: \f(CW\*(C`hostkey\*(C'\fR). This is a printf format string so every \f(CW\*(C`%\*(C'\fR must
584 be doubled. A single \f(CW%s\fR is replaced by the hostname, so you could use
585 paths like \f(CW\*(C`hostkeys/%s\*(C'\fR to be able to share the same config directory
586 between nodes.
587 .Sp
588 Since only the private key file of the current node is used and the
589 private key file should be kept secret per-node to avoid spoofing, it is
590 not recommended to use this feature this way though.
591 .IP "rekey = seconds" 4
592 .IX Item "rekey = seconds"
593 Sets the rekeying interval in seconds (default: \f(CW3607\fR). Connections are
594 reestablished every \f(CW\*(C`rekey\*(C'\fR seconds, making them use a new encryption
595 key.
596 .IP "seed-device = path" 4
597 .IX Item "seed-device = path"
598 The random device used to initially and regularly seed the random
599 number generator (default: \fI/dev/urandom\fR). Randomness is of paramount
600 importance to the security of the algorithms used in gvpe.
601 .Sp
602 On program start and every seed-interval, gvpe will read 64 octets.
603 .Sp
604 Setting this path to the empty string will disable this functionality
605 completely (the underlying crypto library will likely look for entropy
606 sources on it's own though, so not all is lost).
607 .IP "seed-interval = seconds" 4
608 .IX Item "seed-interval = seconds"
609 The number of seconds between reseeds of the random number generator
610 (default: \f(CW3613\fR). A value of \f(CW0\fR disables this regular reseeding.
611 .IP "serial = string" 4
612 .IX Item "serial = string"
613 The configuration serial number. This can be any string up to 16 bytes
614 length. Only when the serial matches on both sides of a connection will
615 the connection succeed. This is \fInot\fR a security mechanism and eay to
616 spoof, this mechanism exists to alert users that their config is outdated.
617 .Sp
618 It's recommended to specify this is a date string such as \f(CW\*(C`2013\-05\-05\*(C'\fR or
619 \&\f(CW20121205084417\fR.
620 .Sp
621 The exact algorithm is as this: if a connection request is received form a
622 node with an identical serial, then it succeeds normally.
623 .Sp
624 If the remote serial is lower than the local serial, it is ignored.
625 .Sp
626 If the remote serial is higher than the local serial, a warning message is
627 logged.
628 .SS "\s-1NODE SPECIFIC SETTINGS\s0"
629 .IX Subsection "NODE SPECIFIC SETTINGS"
630 The following settings are node-specific, that is, every node can have
631 different settings, even within the same gvpe instance. Settings that are
632 set before the first node section set the defaults, settings that are
633 set within a node section only apply to the given node.
634 .IP "allow-direct = nodename" 4
635 .IX Item "allow-direct = nodename"
636 Allow direct connections to this node. See \f(CW\*(C`deny\-direct\*(C'\fR for more info.
637 .IP "compress = yes|true|on | no|false|off" 4
638 .IX Item "compress = yes|true|on | no|false|off"
639 For the current node, this specified whether it will accept compressed
640 packets, and for all other nodes, this specifies whether to try to
641 compress data packets sent to this node (default: \f(CW\*(C`yes\*(C'\fR). Compression is
642 really cheap even on slow computers, has no size overhead at all and will
643 only be used when the other side supports compression, so enabling this is
644 often a good idea.
645 .IP "connect = ondemand | never | always | disabled" 4
646 .IX Item "connect = ondemand | never | always | disabled"
647 Sets the connect mode (default: \f(CW\*(C`always\*(C'\fR). It can be \f(CW\*(C`always\*(C'\fR (always
648 try to establish and keep a connection to the given node), \f(CW\*(C`never\*(C'\fR
649 (never initiate a connection to the given host, but accept connections),
650 \&\f(CW\*(C`ondemand\*(C'\fR (try to establish a connection when there are outstanding
651 packets in the queue and take it down after the keepalive interval) or
652 \&\f(CW\*(C`disabled\*(C'\fR (node is bad, don't talk to it).
653 .Sp
654 Routers will automatically be forced to \f(CW\*(C`always\*(C'\fR unless they are
655 \&\f(CW\*(C`disabled\*(C'\fR, to ensure all nodes can talk to each other.
656 .IP "deny-direct = nodename | *" 4
657 .IX Item "deny-direct = nodename | *"
658 Deny direct connections to the specified node (or all nodes when \f(CW\*(C`*\*(C'\fR
659 is given). Only one node can be specified, but you can use multiple
660 \&\f(CW\*(C`allow\-direct\*(C'\fR and \f(CW\*(C`deny\-direct\*(C'\fR statements. This only makes sense in
661 networks with routers, as routers are required for indirect connections.
662 .Sp
663 Sometimes, a node cannot reach some other nodes for reasons of network
664 connectivity. For example, a node behind a firewall that only allows
665 connections to/from a single other node in the network. In this case one
666 should specify \f(CW\*(C`deny\-direct = *\*(C'\fR and \f(CW\*(C`allow\-direct = othernodename\*(C'\fR (the other
667 node \fImust\fR be a router for this to work).
668 .Sp
669 The algorithm to check whether a connection may be direct is as follows:
670 .Sp
671 1. Other node mentioned in an \f(CW\*(C`allow\-direct\*(C'\fR? If yes, allow the connection.
672 .Sp
673 2. Other node mentioned in a \f(CW\*(C`deny\-direct\*(C'\fR? If yes, deny direct connections.
674 .Sp
675 3. Allow the connection.
676 .Sp
677 That is, \f(CW\*(C`allow\-direct\*(C'\fR takes precedence over \f(CW\*(C`deny\-direct\*(C'\fR.
678 .Sp
679 The check is done in both directions, i.e. both nodes must allow a direct
680 connection before one is attempted, so you only need to specify connect
681 limitations on one node.
682 .IP "dns-domain = domain-suffix" 4
683 .IX Item "dns-domain = domain-suffix"
684 The \s-1DNS\s0 domain suffix that points to the \s-1DNS\s0 tunnel server for this node.
685 .Sp
686 The domain must point to a \s-1NS\s0 record that points to the \fIdns-hostname\fR,
687 i.e.
688 .Sp
689 .Vb 2
690 \& dns\-domainname = tunnel.example.net
691 \& dns\-hostname = tunnel\-server.example.net
692 .Ve
693 .Sp
694 Corresponds to the following \s-1DNS\s0 entries in the \f(CW\*(C`example.net\*(C'\fR domain:
695 .Sp
696 .Vb 2
697 \& tunnel.example.net. NS tunnel\-server.example.net.
698 \& tunnel\-server.example.net. A 13.13.13.13
699 .Ve
700 .IP "dns-hostname = hostname/ip" 4
701 .IX Item "dns-hostname = hostname/ip"
702 The address to bind the \s-1DNS\s0 tunnel socket to, similar to the \f(CW\*(C`hostname\*(C'\fR,
703 but for the \s-1DNS\s0 tunnel protocol only. Default: \f(CW0.0.0.0\fR, but that might
704 change.
705 .IP "dns-port = port-number" 4
706 .IX Item "dns-port = port-number"
707 The port to bind the \s-1DNS\s0 tunnel socket to. Must be \f(CW53\fR on \s-1DNS\s0 tunnel servers.
708 .IP "enable-dns = yes|true|on | no|false|off" 4
709 .IX Item "enable-dns = yes|true|on | no|false|off"
710 See \fIgvpe.protocol\fR\|(7) for a description of the \s-1DNS\s0 transport
711 protocol. Avoid this protocol if you can.
712 .Sp
713 Enable the \s-1DNS\s0 tunneling protocol on this node, either as server or as
714 client. Support for this transport protocol is only available when gvpe
715 was compiled using the \f(CW\*(C`\-\-enable\-dns\*(C'\fR option.
716 .IP "enable-icmp = yes|true|on | no|false|off" 4
717 .IX Item "enable-icmp = yes|true|on | no|false|off"
718 See \fIgvpe.protocol\fR\|(7) for a description of the \s-1ICMP\s0 transport protocol.
719 .Sp
720 Enable the \s-1ICMP\s0 transport using \s-1ICMP\s0 packets of type \f(CW\*(C`icmp\-type\*(C'\fR on this
721 node.
722 .IP "enable-rawip = yes|true|on | no|false|off" 4
723 .IX Item "enable-rawip = yes|true|on | no|false|off"
724 See \fIgvpe.protocol\fR\|(7) for a description of the \s-1RAW IP\s0 transport protocol.
725 .Sp
726 Enable the \s-1RAW\s0 IPv4 transport using the \f(CW\*(C`ip\-proto\*(C'\fR protocol
727 (default: \f(CW\*(C`no\*(C'\fR).
728 .IP "enable-tcp = yes|true|on | no|false|off" 4
729 .IX Item "enable-tcp = yes|true|on | no|false|off"
730 See \fIgvpe.protocol\fR\|(7) for a description of the \s-1TCP\s0 transport protocol.
731 .Sp
732 Enable the TCPv4 transport using the \f(CW\*(C`tcp\-port\*(C'\fR port
733 (default: \f(CW\*(C`no\*(C'\fR). Support for this transport protocol is only available
734 when gvpe was compiled using the \f(CW\*(C`\-\-enable\-tcp\*(C'\fR option.
735 .IP "enable-udp = yes|true|on | no|false|off" 4
736 .IX Item "enable-udp = yes|true|on | no|false|off"
737 See \fIgvpe.protocol\fR\|(7) for a description of the \s-1UDP\s0 transport protocol.
738 .Sp
739 Enable the UDPv4 transport using the \f(CW\*(C`udp\-port\*(C'\fR port (default: \f(CW\*(C`no\*(C'\fR).
740 .IP "hostname = hostname | ip [can not be defaulted]" 4
741 .IX Item "hostname = hostname | ip [can not be defaulted]"
742 Forces the address of this node to be set to the given \s-1DNS\s0 hostname or \s-1IP\s0
743 address. It will be resolved before each connect request, so dyndns should
744 work fine. If this setting is not specified and a router is available,
745 then the router will be queried for the address of this node. Otherwise,
746 the connection attempt will fail.
747 .Sp
748 Note that \s-1DNS\s0 resolving is done synchronously, pausing the daemon. If that
749 is an issue you need to specify \s-1IP\s0 addresses.
750 .IP "icmp-type = integer" 4
751 .IX Item "icmp-type = integer"
752 Sets the type value to be used for outgoing (and incoming) packets sent
753 via the \s-1ICMP\s0 transport.
754 .Sp
755 The default is \f(CW0\fR (which is \f(CW\*(C`echo\-reply\*(C'\fR, also known as
756 \&\*(L"ping-reply\*(R"). Other useful values include \f(CW8\fR (\f(CW\*(C`echo\-request\*(C'\fR, a.k.a.
757 \&\*(L"ping\*(R") and \f(CW11\fR (\f(CW\*(C`time\-exceeded\*(C'\fR), but any 8\-bit value can be used.
758 .IP "if-up-data = value" 4
759 .IX Item "if-up-data = value"
760 The value specified using this directive will be passed to the \f(CW\*(C`if\-up\*(C'\fR
761 script in the environment variable \f(CW\*(C`IFUPDATA\*(C'\fR.
762 .IP "inherit-tos = yes|true|on | no|false|off" 4
763 .IX Item "inherit-tos = yes|true|on | no|false|off"
764 Whether to inherit the \s-1TOS\s0 settings of packets sent to the tunnel when
765 sending packets to this node (default: \f(CW\*(C`yes\*(C'\fR). If set to \f(CW\*(C`yes\*(C'\fR then
766 outgoing tunnel packets will have the same \s-1TOS\s0 setting as the packets sent
767 to the tunnel device, which is usually what you want.
768 .IP "low-power = yes|true|on | no|false|off" 4
769 .IX Item "low-power = yes|true|on | no|false|off"
770 If true, designates a node as a low-power node. Low-power nodes use
771 larger timeouts and try to reduce cpu time. Other nodes talking to a
772 low-power node will also use larger timeouts, and will use less aggressive
773 optimisations, in the hope of reducing load. Security is not compromised.
774 .Sp
775 The typical low-power node would be a mobile phone, where wakeups and
776 encryption can significantly increase power drain.
777 .IP "max-retry = positive-number" 4
778 .IX Item "max-retry = positive-number"
779 The maximum interval in seconds (default: \f(CW3600\fR, one hour) between
780 retries to establish a connection to this node. When a connection cannot
781 be established, gvpe uses exponential back-off capped at this value. It's
782 sometimes useful to set this to a much lower value (e.g. \f(CW120\fR) on
783 connections to routers that usually are stable but sometimes are down, to
784 assure quick reconnections even after longer downtimes.
785 .IP "max-ttl = seconds" 4
786 .IX Item "max-ttl = seconds"
787 Expire packets that couldn't be sent after this many seconds
788 (default: \f(CW60\fR). Gvpe will normally queue packets for a node without an
789 active connection, in the hope of establishing a connection soon. This
790 value specifies the maximum lifetime a packet will stay in the queue, if a
791 packet gets older, it will be thrown away.
792 .IP "max-queue = positive\-number>=1" 4
793 .IX Item "max-queue = positive-number>=1"
794 The maximum number of packets that will be queued (default: \f(CW512\fR)
795 for this node. If more packets are sent then earlier packets will be
796 expired. See \f(CW\*(C`max\-ttl\*(C'\fR, above.
797 .IP "router-priority = 0 | 1 | positive\-number>=2" 4
798 .IX Item "router-priority = 0 | 1 | positive-number>=2"
799 Sets the router priority of the given node (default: \f(CW0\fR, disabled).
800 .Sp
801 If some node tries to connect to another node but it doesn't have a
802 hostname, it asks a router node for it's \s-1IP\s0 address. The router node
803 chosen is the one with the highest priority larger than \f(CW1\fR that is
804 currently reachable. This is called a \fImediated\fR connection, as the
805 connection itself will still be direct, but it uses another node to
806 mediate between the two nodes.
807 .Sp
808 The value \f(CW0\fR disables routing, that means if the node receives a packet
809 not for itself it will not forward it but instead drop it.
810 .Sp
811 The special value \f(CW1\fR allows other hosts to route through the router
812 host, but they will never route through it by default (i.e. the config
813 file of another node needs to specify a router priority higher than one
814 to choose such a node for routing).
815 .Sp
816 The idea behind this is that some hosts can, if required, bump the
817 \&\f(CW\*(C`router\-priority\*(C'\fR setting to higher than \f(CW1\fR in their local config to
818 route through specific hosts. If \f(CW\*(C`router\-priority\*(C'\fR is \f(CW0\fR, then routing
819 will be refused, so \f(CW1\fR serves as a \*(L"enable, but do not use by default\*(R"
820 switch.
821 .Sp
822 Nodes with \f(CW\*(C`router\-priority\*(C'\fR set to \f(CW2\fR or higher will always be forced
823 to \f(CW\*(C`connect\*(C'\fR = \f(CW\*(C`always\*(C'\fR (unless they are \f(CW\*(C`disabled\*(C'\fR).
824 .IP "tcp-port = port-number" 4
825 .IX Item "tcp-port = port-number"
826 Similar to \f(CW\*(C`udp\-port\*(C'\fR (default: \f(CW655\fR), but sets the \s-1TCP\s0 port number.
827 .IP "udp-port = port-number" 4
828 .IX Item "udp-port = port-number"
829 Sets the port number used by the \s-1UDP\s0 protocol (default: \f(CW655\fR, not
830 officially assigned by \s-1IANA\s0!).
831 .SH "CONFIG DIRECTORY LAYOUT"
832 .IX Header "CONFIG DIRECTORY LAYOUT"
833 The default (or recommended) directory layout for the config directory is:
834 .IP "gvpe.conf" 4
835 .IX Item "gvpe.conf"
836 The config file.
837 .IP "if-up" 4
838 .IX Item "if-up"
839 The if-up script
840 .IP "node-up, node-down" 4
841 .IX Item "node-up, node-down"
842 If used the node up or node-down scripts.
843 .IP "hostkey" 4
844 .IX Item "hostkey"
845 The (default path of the) private key of the current host.
846 .IP "pubkey/nodename" 4
847 .IX Item "pubkey/nodename"
848 The public keys of the other nodes, one file per node.
849 .SH "SEE ALSO"
850 .IX Header "SEE ALSO"
851 \&\fIgvpe\fR\|(5), \fIgvpe\fR\|(8), \fIgvpectrl\fR\|(8).
852 .SH "AUTHOR"
853 .IX Header "AUTHOR"
854 Marc Lehmann <gvpe@schmorp.de>