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Revision 1.3 by pcg, Sat Dec 4 18:38:28 2004 UTC vs.
Revision 1.25 by pcg, Fri Sep 10 21:13:52 2010 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 33The only exception to the above is the "on" directive that can prefix any
31C<name = value> setting and will only "execute" it on the named node, or 34C<name = value> setting and will only "execute" it on the named node, or
32(if the nodename starts with "!") on all nodes except the named one. 35(if the nodename starts with "!") on all nodes except the named one.
33 36
34 name = value 37For example, set the MTU to C<1450> everywhere, loglevel to C<noise> on
38branch1, and connect to C<ondemand> everywhere but on branch2:
39
40 mtu = 1450
35 on branch1 loglevel = noise 41 on branch1 loglevel = noise
36 on !branch2 connect = ondemand 42 on !branch2 connect = ondemand
37 43
38All settings are executed "in order", that is, later settings of the same 44All settings are applied "in order", that is, later settings of the same
39variable overwrite earlier ones. 45variable overwrite earlier ones.
40 46
41=head1 ANATOMY OF A CONFIG FILE 47=head1 ANATOMY OF A CONFIG FILE
42 48
43Usually, a config file starts with global settings (like the udp port to 49Usually, 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 = 50port to listen on), followed by node-specific sections that begin with a
45nickname> line. 51C<node = nickname> line.
46 52
47Every node that is part of the network must have a section that starts 53Every 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 54with 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 55and must be the same on all nodes. It is not uncommon for node sections to
50be completely empty - if the default values are right. 56be completely empty - if the default values are right.
51 57
52Node-specific settings can be used at any time. If used before the first 58Node-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. 59node section they will set the default values for all following nodes.
54 60
61values on different nodes using C<on>), but will affect the behaviour of 67values on different nodes using C<on>), but will affect the behaviour of
62the gvpe daemon and all connections it creates. 68the gvpe daemon and all connections it creates.
63 69
64=over 4 70=over 4
65 71
66=item loglevel = noise|trace|debug|info|notice|warn|error|critical 72=item dns-forw-host = hostname/ip
67 73
68Set the logging level. Connection established messages are logged at level 74The DNS server to forward DNS requests to for the DNS tunnel protocol
69C<info>, notable errors are logged with C<error>. Default is C<info>. 75(default: C<127.0.0.1>, changing it is highly recommended).
70 76
71=item node = nickname 77=item dns-forw-port = port-number
72 78
73Not really a config setting but introduces a node section. The nickname is 79The port where the C<dns-forw-host> is to be contacted (default: C<53>,
74used to select the right configuration section and must be passed as an 80which is fine in most cases).
75argument to the gvpe daemon.
76 81
77=item private-key = relative-path-to-key 82=item dns-max-outstanding = integer-number-of-requests
78 83
79Sets the path (relative to the config directory) to the private key 84The maximum number of outstanding DNS transport requests
80(default: C<hostkey>). This is a printf format string so every C<%> must 85(default: C<100>). GVPE will never issue more requests then the given
81be doubled. A single C<%s> is replaced by the hostname, so you could 86limit without receiving replies. In heavily overloaded situations it might
82use paths like C<hostkeys/%s> to fetch the files at the location where 87help to set this to a low number (e.g. C<3> or even C<1>) to limit the
83C<gvpectrl> puts them. 88number of parallel requests.
84 89
85Since only the private key file of the current node is used and the 90The default should be working OK for most links.
86private key file should be kept secret per-host to avoid spoofings, it is 91
87not recommended to use this feature. 92=item dns-overlap-factor = float
93
94The DNS transport uses the minimum request latency (B<min_latency>) seen
95during a connection as it's timing base. This factor (default: C<0.5>,
96must be > 0) is multiplied by B<min_latency> to get the maximum sending
97rate (= minimum send interval), i.e. a factor of C<1> means that a new
98request might be generated every B<min_latency> seconds, which means on
99average there should only ever be one outstanding request. A factor of
100C<0.5> means that GVPE will send requests twice as often as the minimum
101latency measured.
102
103For congested or picky DNS forwarders you could use a value nearer to or
104exceeding C<1>.
105
106The default should be working OK for most links.
107
108=item dns-send-interval = send-interval-in-seconds
109
110The minimum send interval (= maximum rate) that the DNS transport will
111use to send new DNS requests. GVPE will not exceed this rate even when
112the latency is very low. The default is C<0.01>, which means GVPE will
113not send more than 100 DNS requests per connection per second. For
114high-bandwidth links you could go lower, e.g. to C<0.001> or so. For
115congested or rate-limited links, you might want to go higher, say C<0.1>,
116C<0.2> or even higher.
117
118The default should be working OK for most links.
119
120=item dns-timeout-factor = float
121
122Factor to multiply the C<min_latency> (see C<dns-overlap-factor>) by to
123get request timeouts. The default of C<8> means that the DNS transport
124will resend the request when no reply has been received for longer than
125eight times the minimum (= expected) latency, assuming the request or
126reply has been lost.
127
128For congested links a higher value might be necessary (e.g. C<30>). If
129the link is very stable lower values (e.g. C<2>) might work
130nicely. Values near or below C<1> makes no sense whatsoever.
131
132The default should be working OK for most links but will result in low
133throughput if packet loss is high.
134
135=item if-up = relative-or-absolute-path
136
137Sets the path of a script that should be called immediately after the
138network interface is initialized (but not necessarily up). The following
139environment variables are passed to it (the values are just examples).
140
141Variables that have the same value on all nodes:
142
143=over 4
144
145=item CONFBASE=/etc/gvpe
146
147The configuration base directory.
148
149=item IFNAME=vpn0
150
151The network interface to initialize.
152
153=item IFTYPE=native # or tincd
154
155=item IFSUBTYPE=linux # or freebsd, darwin etc..
156
157The interface type (C<native> or C<tincd>) and the subtype (usually the
158OS name in lowercase) that this GVPE was configured for. Can be used to
159select the correct syntax to use for network-related commands.
160
161=item MTU=1436
162
163The MTU to set the interface to. You can use lower values (if done
164consistently on all nodes), but this is usually either inefficient or
165simply ineffective.
166
167=item NODES=5
168
169The number of nodes in this GVPE network.
170
171=back
172
173Variables that are node-specific and with values pertaining to the node
174running this GVPE:
175
176=over 4
177
178=item IFUPDATA=string
179
180The value of the configuration directive C<if-up-data>.
181
182=item MAC=fe:fd:80:00:00:01
183
184The MAC address the network interface has to use.
185
186Might be used to initialize interfaces on platforms where GVPE does not
187do this automatically. Please see the C<gvpe.osdep(5)> man page for
188platform-specific information.
189
190=item NODENAME=branch1
191
192The nickname of the node.
193
194=item NODEID=1
195
196The numerical node ID of the node running this instance of GVPE. The first
197node mentioned in the config file gets ID 1, the second ID 2 and so on.
198
199=back
200
201In addition, all node-specific variables (except C<NODEID>) will be
202available with a postfix of C<_nodeid>, which contains the value for that
203node, e.g. the C<MAC_1> variable contains the MAC address of node #1, while
204the C<NODENAME_22> variable contains the name of node #22.
205
206Here is a simple if-up script:
207
208 #!/bin/sh
209 ip link set $IFNAME up
210 [ $NODENAME = branch1 ] && ip addr add 10.0.0.1 dev $IFNAME
211 [ $NODENAME = branch2 ] && ip addr add 10.1.0.1 dev $IFNAME
212 ip route add 10.0.0.0/8 dev $IFNAME
213
214More complicated examples (using routing to reduce ARP traffic) can be
215found in the F<etc/> subdirectory of the distribution.
216
217=item ifname = devname
218
219Sets the tun interface name to the given name. The default is OS-specific
220and most probably something like C<tun0>.
88 221
89=item ifpersist = yes|true|on | no|false|off 222=item ifpersist = yes|true|on | no|false|off
90 223
91Should the tun/tap device be made persistent, that is, should the device 224Should 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 225stay up even when gvpe exits? Some versions of the tunnel device have
93problems sending packets when gvpe is restarted in persistent mode, so 226problems sending packets when gvpe is restarted in persistent mode, so
94if the connections can be established but you cannot send packets from 227if 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 228the local node, try to set this to C<off> and do an ifconfig down on the
96device. 229device.
97 230
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 231=item ip-proto = numerical-ip-protocol
128 232
129Sets the protocol number to be used for the rawip protocol. This is a 233Sets 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 234global option because all nodes must use the same protocol, and since
131there are no port numbers, you cannot easily run more than one gvpe 235there are no port numbers, you cannot easily run more than one gvpe
132instance using the same protocol, nor can you share the protocol with 236instance using the same protocol, nor can you share the protocol with
133other programs. 237other programs.
134 238
135The default is 47 (GRE), which has a good chance of tunneling through 239The default is 47 (GRE), which has a good chance of tunneling
136firewalls (but note that the rawip protocol is not GRE compatible). Other 240through 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 241compatible). Other common choices are 50 (IPSEC, ESP), 51 (IPSEC, AH), 4
138(ENCAP, rfc1241) 242(IPIP tunnels) or 98 (ENCAP, rfc1241).
139 243
244Many versions of Linux seem to have a bug that causes them to reorder
245packets for some ip protocols (GRE, ESP) but not for others (AH), so
246choose wisely (that is, use 51, AH).
247
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 nodes) 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 nodes.
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,
282separated by a literal colon (C<:>). Only basic authentication is
283currently supported.
284
285=item keepalive = seconds
286
287Sets the keepalive probe interval in seconds (default: C<60>). After this
288many seconds of inactivity the daemon will start to send keepalive probe
289every 3 seconds until it receives a reply from the other end. If no reply
290is received within 15 seconds, the peer is considered unreachable and the
291connection is closed.
292
293=item loglevel = noise|trace|debug|info|notice|warn|error|critical
294
295Set the logging level. Connection established messages are logged at level
296C<info>, notable errors are logged with C<error>. Default is C<info>.
297
298=item mtu = bytes
299
300Sets the maximum MTU that should be used on outgoing packets (basically
301the MTU of the outgoing interface) The daemon will automatically calculate
302maximum overhead (e.g. UDP header size, encryption blocksize...) and pass
303this information to the C<if-up> script.
304
305Recommended values are 1500 (ethernet), 1492 (pppoe), 1472 (pptp).
306
307This value must be the minimum of the MTU values of all nodes.
308
309=item node = nickname
310
311Not really a config setting but introduces a node section. The nickname is
312used to select the right configuration section and must be passed as an
313argument to the gvpe daemon.
314
140=item if-up = relative-or-absolute-path 315=item node-up = relative-or-absolute-path
141 316
142Sets the path of a script that should be called immediately after the 317Sets a command (default: none) that should be called whenever a connection
143network interface is initialized (but not neccessarily up). The following 318is established (even on rekeying operations). Note that node-up/down
319scripts will be run asynchronously, but execution is serialised, so there
320will only ever be one such script running.
321
322In addition to all the variables passed to C<if-up> scripts, the following
144environment variables are passed to it (the values are just examples): 323environment variables will be set (values are just examples):
145 324
146=over 4 325=over 4
147 326
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 327=item DESTNODE=branch2
180 328
181The nickname of the current node, as passed to the gvpe daemon. 329The name of the remote node.
182 330
183=item NODEID=1 331=item DESTID=2
184 332
185The numerical node id of the current node. The first node mentioned in the 333The node id of the remote node.
186config file gets ID 1, the second ID 2 and so on. 334
335=item DESTSI=rawip/88.99.77.55:0
336
337The "socket info" of the target node, protocol dependent but usually in
338the format protocol/ip:port.
339
340=item DESTIP=188.13.66.8
341
342The numerical IP address of the remote node (gvpe accepts connections from
343everywhere, as long as the other node can authenticate itself).
344
345=item DESTPORT=655 # deprecated
346
347The protocol port used by the other side, if applicable.
348
349=item STATE=up
350
351Node-up scripts get called with STATE=up, node-change scripts get called
352with STATE=change and node-down scripts get called with STATE=down.
187 353
188=back 354=back
189 355
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 356Here is a nontrivial example that uses nsupdate to update the name => ip
235mapping in some dns zone: 357mapping in some DNS zone:
236 358
237 #!/bin/sh 359 #!/bin/sh
238 { 360 {
239 echo update delete $DESTNODE.lowttl.example.net. a 361 echo update delete $DESTNODE.lowttl.example.net. a
240 echo update add $DESTNODE.lowttl.example.net. 1 in a $DESTIP 362 echo update add $DESTNODE.lowttl.example.net. 1 in a $DESTIP
241 echo 363 echo
242 } | nsupdate -d -k $CONFBASE:key.example.net. 364 } | nsupdate -d -k $CONFBASE:key.example.net.
243 365
366=item node-change = relative-or-absolute-path
367
368Same as C<node-change>, but gets called whenever something about a
369connection changes (such as the source IP address).
370
244=item node-down = relative-or-absolute-path 371=item node-down = relative-or-absolute-path
245 372
246Same as C<node-up>, but gets called whenever a connection is lost. 373Same as C<node-up>, but gets called whenever a connection is lost.
247 374
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 375=item pid-file = path
286 376
287The path to the pid file to check and create (Default: 377The path to the pid file to check and create
378(default: C<LOCALSTATEDIR/run/gvpe.pid>).
379
380=item private-key = relative-path-to-key
381
382Sets the path (relative to the config directory) to the private key
383(default: C<hostkey>). This is a printf format string so every C<%> must
384be doubled. A single C<%s> is replaced by the hostname, so you could
385use paths like C<hostkeys/%s> to fetch the files at the location where
386C<gvpectrl> puts them.
387
388Since only the private key file of the current node is used and the
389private key file should be kept secret per-node to avoid spoofing, it is
390not recommended to use this feature.
391
392=item rekey = seconds
393
394Sets the rekeying interval in seconds (default: C<3600>). Connections are
395reestablished every C<rekey> seconds, making them use a new encryption
396key.
397
398=item nfmark = integer
399
400This advanced option, when set to a nonzero value (default: C<0>), tries
401to set the netfilter mark (or fwmark) value on all sockets gvpe uses to
402send packets.
403
404This can be used to make gvpe use a different set of routing rules. For
405example, on GNU/Linux, the C<if-up> could set C<nfmark> to 1000 and then
406put all routing rules into table C<99> and then use an ip rule to make
407gvpe traffic avoid that routing table, in effect routing normal traffic
408via gvpe and gvpe traffic via the normal system routing tables:
409
410 ip rule add not fwmark 1000 lookup 99
288 411
289=back 412=back
290 413
291=head2 NODE SPECIFIC SETTINGS 414=head2 NODE SPECIFIC SETTINGS
292 415
293The following settings are node-specific, that is, every node can have 416The following settings are node-specific, that is, every node can have
294different settings, even within the same gvpe instance. Settings that are 417different settings, even within the same gvpe instance. Settings that are
295executed before the first node section set the defaults, settings that are 418set before the first node section set the defaults, settings that are
296executed within a node section only apply to the given node. 419set within a node section only apply to the given node.
297 420
298=over 4 421=over 4
299 422
423=item allow-direct = nodename
424
425Allow direct connections to this node. See C<deny-direct> for more info.
426
427=item compress = yes|true|on | no|false|off
428
429Wether to compress data packets sent to this node (default: C<yes>).
430Compression is really cheap even on slow computers and has no size
431overhead at all, so enabling this is often a good idea.
432
433=item connect = ondemand | never | always | disabled
434
435Sets the connect mode (default: C<always>). It can be C<always> (always
436try to establish and keep a connection to the given node), C<never>
437(never initiate a connection to the given host, but accept connections),
438C<ondemand> (try to establish a connection when there are outstanding
439packets in the queue and take it down after the keepalive interval) or
440C<disabled> (node is bad, don't talk to it).
441
442Routers will automatically be forced to C<always> unless they are
443C<disabled>, to ensure all nodes can talk to each other.
444
445=item deny-direct = nodename | *
446
447Deny direct connections to the specified node (or all nodes when C<*>
448is given). Only one node can be specified, but you can use multiple
449C<allow-direct> and C<deny-direct> statements. This only makes sense in
450networks with routers, as routers are required for indirect connections.
451
452Sometimes, a node cannot reach some other nodes for reasons of network
453connectivity. For example, a node behind a firewall that only allows
454connections to/from a single other node in the network. In this case one
455should specify C<deny-direct = *> and C<allow-direct = othernodename> (the other
456node I<must> be a router for this to work).
457
458The algorithm to check whether a connection may be direct is as follows:
459
4601. Other node mentioned in an C<allow-direct>? If yes, allow the connection.
461
4622. Other node mentioned in a C<deny-direct>? If yes, deny direct connections.
463
4643. Allow the connection.
465
466That is, C<allow-direct> takes precedence over C<deny-direct>.
467
468The check is done in both directions, i.e. both nodes must allow a direct
469connection before one is attempted, so you only need to specify connect
470limitations on one node.
471
472=item dns-domain = domain-suffix
473
474The DNS domain suffix that points to the DNS tunnel server for this node.
475
476The domain must point to a NS record that points to the I<dns-hostname>,
477i.e.
478
479 dns-domainname = tunnel.example.net
480 dns-hostname = tunnel-server.example.net
481
482Corresponds to the following DNS entries in the C<example.net> domain:
483
484 tunnel.example.net. NS tunnel-server.example.net.
485 tunnel-server.example.net. A 13.13.13.13
486
487=item dns-hostname = hostname/ip
488
489The address to bind the DNS tunnel socket to, similar to the C<hostname>,
490but for the DNS tunnel protocol only. Default: C<0.0.0.0>, but that might
491change.
492
300=item udp-port = port-number 493=item dns-port = port-number
301 494
302Sets the port number used by the UDP protocol (default: C<655>, not 495The port to bind the DNS tunnel socket to. Must be C<53> on DNS tunnel servers.
303officially assigned by IANA!).
304 496
305=item tcp-port = port-number 497=item enable-dns = yes|true|on | no|false|off
306 498
307Similar to C<udp-port> (default: C<655>), but sets the TCP port number. 499See gvpe.protocol(7) for a description of the DNS transport
500protocol. Avoid this protocol if you can.
501
502Enable the DNS tunneling protocol on this node, either as server or as
503client. Support for this transport protocol is only available when gvpe
504was compiled using the C<--enable-dns> option.
505
506=item enable-icmp = yes|true|on | no|false|off
507
508See gvpe.protocol(7) for a description of the ICMP transport protocol.
509
510Enable the ICMP transport using ICMP packets of type C<icmp-type> on this
511node.
308 512
309=item enable-rawip = yes|true|on | no|false|off 513=item enable-rawip = yes|true|on | no|false|off
310 514
515See gvpe.protocol(7) for a description of the RAW IP transport protocol.
516
311Enable the RAW IPv4 transport using the C<ip-proto> protocol 517Enable the RAW IPv4 transport using the C<ip-proto> protocol
312(default: C<no>). This is the best choice, since the overhead per packet 518(default: C<no>).
313is only 38 bytes, as opposed to UDP's 58 (or TCP's 60+). 519
520=item enable-tcp = yes|true|on | no|false|off
521
522See gvpe.protocol(7) for a description of the TCP transport protocol.
523
524Enable the TCPv4 transport using the C<tcp-port> port
525(default: C<no>). Support for this transport protocol is only available
526when gvpe was compiled using the C<--enable-tcp> option.
314 527
315=item enable-udp = yes|true|on | no|false|off 528=item enable-udp = yes|true|on | no|false|off
316 529
530See gvpe.protocol(7) for a description of the UDP transport protocol.
531
317Enable the UDPv4 transport using the C<udp-port> port (default: C<yes>, 532Enable 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 533unless no other protocol is enabled for a node, in which case this
319well through many firewalls. 534protocol is enabled automatically).
320 535
321NOTE: Please specify C<enable-udp = yes> even though it is the default, as 536NOTE: Please specify C<enable-udp = yes> if you want to use it even though
322some future version will have all protocols disabled by default. 537it might get switched on automatically, as some future version might
538default to another default protocol.
323 539
324=item enable-tcp = yes|true|on | no|false|off 540=item hostname = hostname | ip [can not be defaulted]
325 541
326Enable the TCPv4 transport using the C<tcp-port> port 542Forces the address of this node to be set to the given DNS hostname or IP
327(default: C<no>). Support for this horribly unsuitable protocol is only 543address. It will be resolved before each connect request, so dyndns should
328available when gvpe was compiled using the C<--enable-tcp> option. Never 544work fine. If this setting is not specified and a router is available,
329use this transport unless you really must, it is horribly ineffiecent and 545then the router will be queried for the address of this node. Otherwise,
330resource-intensive compared to the other transports. 546the connection attempt will fail.
331 547
332=item router-priority = 0 | 1 | positive-number>2 548Note that DNS resolving is done synchronously, pausing the daemon. If that
549is an issue you need to specify IP addresses.
333 550
334Sets the router priority of the given host (default: C<0>, disabled). If 551=item icmp-type = integer
335some host tries to connect to another host without a hostname, it asks
336the router host for it's IP address. The router host is the one with the
337highest priority larger than C<1> that is currently reachable.
338 552
339Make sure all hosts always connect (C<connect = always>) to the router 553Sets the type value to be used for outgoing (and incoming) packets sent
340hosts, otherwise connecting to them might be impossible. 554via the ICMP transport.
341 555
342The special value C<1> allows other hosts to route through the router 556The default is C<0> (which is C<echo-reply>, also known as
343host, but they will never route through it by default. The value C<0> 557"ping-reply"). Other useful values include C<8> (C<echo-request>, a.k.a.
344disables routing. The idea behind this is that some hosts can, if 558"ping") and C<11> (C<time-exceeded>), but any 8-bit value can be used.
345required, bump the C<router-priority> setting to higher than C<1> in their
346local config to route through specific hosts. If C<router-priority> is
347C<0>, then routing will be refused, so C<1> serves as a "enable, but do
348not use by default" switch.
349 559
350=item connect = ondemand | never | always | disabled 560=item if-up-data = value
351 561
352Sets the connect mode (default: C<always>). It can be C<always> (always 562The value specified using this directive will be passed to the C<if-up>
353try to establish and keep a connection to the given host), C<never> 563script in the environment variable C<IFUPDATA>.
354(never initiate a connection to the given host, but accept connections),
355C<ondemand> (try to establish a connection on the first packet sent, and
356take it down after the keepalive interval) or C<disabled> (node is bad,
357don't talk to it).
358 564
359=item inherit-tos = yes|true|on | no|false|off 565=item inherit-tos = yes|true|on | no|false|off
360 566
361Wether to inherit the TOS settings of packets sent to the tunnel when 567Wether to inherit the TOS settings of packets sent to the tunnel when
362sending packets to this node (default: C<yes>). If set to C<yes> then 568sending packets to this node (default: C<yes>). If set to C<yes> then
363outgoing tunnel packets will have the same TOS setting as the packets sent 569outgoing tunnel packets will have the same TOS setting as the packets sent
364to the tunnel device, which is usually what you want. 570to the tunnel device, which is usually what you want.
365 571
366=item compress = yes|true|on | no|false|off
367
368Wether to compress data packets sent to this host (default: C<yes>).
369Compression is really cheap even on slow computers and has no size
370overhead at all, so enabling this is a good idea.
371
372=item max-retry = positive-number 572=item max-retry = positive-number
373 573
374The maximum interval in seconds (default: C<28800>, 8 hours) between 574The maximum interval in seconds (default: C<3600>, one hour) between
375retries to establish a connection to this node. When a connection cannot 575retries to establish a connection to this node. When a connection cannot
376be established, gvpe uses exponential backoff capped at this value. It's 576be established, gvpe uses exponential back-off capped at this value. It's
377sometimes useful to set this to a much lower value (e.g. C<120>) on 577sometimes useful to set this to a much lower value (e.g. C<120>) on
378connections to routers that usually are stable but sometimes are down, to 578connections to routers that usually are stable but sometimes are down, to
379assure quick reconnections. 579assure quick reconnections even after longer downtimes.
580
581=item max-ttl = seconds
582
583Expire packets that couldn't be sent after this many seconds
584(default: C<60>). Gvpe will normally queue packets for a node without an
585active connection, in the hope of establishing a connection soon. This
586value specifies the maximum lifetime a packet will stay in the queue, if a
587packet gets older, it will be thrown away.
588
589=item max-queue = positive-number>=1
590
591The maximum number of packets that will be queued (default: C<512>)
592for this node. If more packets are sent then earlier packets will be
593expired. See C<max-ttl>, above.
594
595=item router-priority = 0 | 1 | positive-number>=2
596
597Sets the router priority of the given node (default: C<0>, disabled).
598
599If some node tries to connect to another node but it doesn't have a
600hostname, it asks a router node for it's IP address. The router node
601chosen is the one with the highest priority larger than C<1> that is
602currently reachable. This is called a I<mediated> connection, as the
603connection itself will still be direct, but it uses another node to
604mediate between the two nodes.
605
606The value C<0> disables routing, that means if the node receives a packet
607not for itself it will not forward it but instead drop it.
608
609The special value C<1> allows other hosts to route through the router
610host, but they will never route through it by default (i.e. the config
611file of another node needs to specify a router priority higher than one
612to choose such a node for routing).
613
614The idea behind this is that some hosts can, if required, bump the
615C<router-priority> setting to higher than C<1> in their local config to
616route through specific hosts. If C<router-priority> is C<0>, then routing
617will be refused, so C<1> serves as a "enable, but do not use by default"
618switch.
619
620Nodes with C<router-priority> set to C<2> or higher will always be forced
621to C<connect> = C<always> (unless they are C<disabled>).
622
623=item tcp-port = port-number
624
625Similar to C<udp-port> (default: C<655>), but sets the TCP port number.
626
627=item udp-port = port-number
628
629Sets the port number used by the UDP protocol (default: C<655>, not
630officially assigned by IANA!).
380 631
381=back 632=back
382 633
383=head1 CONFIG DIRECTORY LAYOUT 634=head1 CONFIG DIRECTORY LAYOUT
384 635
412 663
413gvpe(5), gvpe(8), gvpectrl(8). 664gvpe(5), gvpe(8), gvpectrl(8).
414 665
415=head1 AUTHOR 666=head1 AUTHOR
416 667
417Marc Lehmann <gvpe@plan9.de> 668Marc Lehmann <gvpe@schmorp.de>
418 669

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