ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/gvpe/doc/gvpe.conf.5.pod
(Generate patch)

Comparing gvpe/doc/gvpe.conf.5.pod (file contents):
Revision 1.1 by pcg, Fri Jun 11 15:56:13 2004 UTC vs.
Revision 1.26 by root, Sat Feb 12 04:15:29 2011 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
429For the current node, this specified whether it will accept compressed
430packets, and for all other nodes, this specifies whether to try to
431compress data packets sent to this node (default: C<yes>). Compression is
432really cheap even on slow computers, has no size overhead at all and will
433only be used when the other side supports compression, so enabling this is
434often a good idea.
435
436=item connect = ondemand | never | always | disabled
437
438Sets the connect mode (default: C<always>). It can be C<always> (always
439try to establish and keep a connection to the given node), C<never>
440(never initiate a connection to the given host, but accept connections),
441C<ondemand> (try to establish a connection when there are outstanding
442packets in the queue and take it down after the keepalive interval) or
443C<disabled> (node is bad, don't talk to it).
444
445Routers will automatically be forced to C<always> unless they are
446C<disabled>, to ensure all nodes can talk to each other.
447
448=item deny-direct = nodename | *
449
450Deny direct connections to the specified node (or all nodes when C<*>
451is given). Only one node can be specified, but you can use multiple
452C<allow-direct> and C<deny-direct> statements. This only makes sense in
453networks with routers, as routers are required for indirect connections.
454
455Sometimes, a node cannot reach some other nodes for reasons of network
456connectivity. For example, a node behind a firewall that only allows
457connections to/from a single other node in the network. In this case one
458should specify C<deny-direct = *> and C<allow-direct = othernodename> (the other
459node I<must> be a router for this to work).
460
461The algorithm to check whether a connection may be direct is as follows:
462
4631. Other node mentioned in an C<allow-direct>? If yes, allow the connection.
464
4652. Other node mentioned in a C<deny-direct>? If yes, deny direct connections.
466
4673. Allow the connection.
468
469That is, C<allow-direct> takes precedence over C<deny-direct>.
470
471The check is done in both directions, i.e. both nodes must allow a direct
472connection before one is attempted, so you only need to specify connect
473limitations on one node.
474
475=item dns-domain = domain-suffix
476
477The DNS domain suffix that points to the DNS tunnel server for this node.
478
479The domain must point to a NS record that points to the I<dns-hostname>,
480i.e.
481
482 dns-domainname = tunnel.example.net
483 dns-hostname = tunnel-server.example.net
484
485Corresponds to the following DNS entries in the C<example.net> domain:
486
487 tunnel.example.net. NS tunnel-server.example.net.
488 tunnel-server.example.net. A 13.13.13.13
489
490=item dns-hostname = hostname/ip
491
492The address to bind the DNS tunnel socket to, similar to the C<hostname>,
493but for the DNS tunnel protocol only. Default: C<0.0.0.0>, but that might
494change.
495
300=item udp-port = port-number 496=item dns-port = port-number
301 497
302Sets the port number used by the UDP protocol (default: C<655>, not 498The port to bind the DNS tunnel socket to. Must be C<53> on DNS tunnel servers.
303officially assigned by IANA!).
304 499
305=item tcp-port = port-number 500=item enable-dns = yes|true|on | no|false|off
306 501
307Similar to C<udp-port> (default: C<655>), but sets the TCP port number. 502See gvpe.protocol(7) for a description of the DNS transport
503protocol. Avoid this protocol if you can.
504
505Enable the DNS tunneling protocol on this node, either as server or as
506client. Support for this transport protocol is only available when gvpe
507was compiled using the C<--enable-dns> option.
508
509=item enable-icmp = yes|true|on | no|false|off
510
511See gvpe.protocol(7) for a description of the ICMP transport protocol.
512
513Enable the ICMP transport using ICMP packets of type C<icmp-type> on this
514node.
308 515
309=item enable-rawip = yes|true|on | no|false|off 516=item enable-rawip = yes|true|on | no|false|off
310 517
518See gvpe.protocol(7) for a description of the RAW IP transport protocol.
519
311Enable the RAW IPv4 transport using the C<ip-proto> protocol 520Enable the RAW IPv4 transport using the C<ip-proto> protocol
312(default: C<no>). This is the best choice, since the overhead per packet 521(default: C<no>).
313is only 38 bytes, as opposed to UDP's 58 (or TCP's 60+). 522
523=item enable-tcp = yes|true|on | no|false|off
524
525See gvpe.protocol(7) for a description of the TCP transport protocol.
526
527Enable the TCPv4 transport using the C<tcp-port> port
528(default: C<no>). Support for this transport protocol is only available
529when gvpe was compiled using the C<--enable-tcp> option.
314 530
315=item enable-udp = yes|true|on | no|false|off 531=item enable-udp = yes|true|on | no|false|off
316 532
533See gvpe.protocol(7) for a description of the UDP transport protocol.
534
317Enable the UDPv4 transport using the C<udp-port> port (default: C<yes>, 535Enable 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 536unless no other protocol is enabled for a node, in which case this
319well through many firewalls. 537protocol is enabled automatically).
320 538
321NOTE: Please specify C<enable-udp = yes> even though it is the default, as 539NOTE: Please specify C<enable-udp = yes> if you want to use it even though
322some future version will have all protocols disabled by default. 540it might get switched on automatically, as some future version might
541default to another default protocol.
323 542
324=item enable-tcp = yes|true|on | no|false|off 543=item hostname = hostname | ip [can not be defaulted]
325 544
326Enable the TCPv4 transport using the C<tcp-port> port 545Forces 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 546address. It will be resolved before each connect request, so dyndns should
328available when gvpe was compiled using the C<--enable-tcp> option. Never 547work fine. If this setting is not specified and a router is available,
329use this transport unless you really must, it is horribly ineffiecent and 548then the router will be queried for the address of this node. Otherwise,
330resource-intensive compared to the other transports. 549the connection attempt will fail.
331 550
332=item router-priority = positive-number 551Note that DNS resolving is done synchronously, pausing the daemon. If that
552is an issue you need to specify IP addresses.
333 553
334Sets the router priority of the given host (default: C<0>, disabled). If 554=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 that is currently reachable. Make sure all clients always
338connect to the router hosts, otherwise conencting to them is impossible.
339 555
340=item connect = ondemand|never|always|disabled 556Sets the type value to be used for outgoing (and incoming) packets sent
557via the ICMP transport.
341 558
342Sets the connect mode (default: C<always>). It can be C<always> (always 559The default is C<0> (which is C<echo-reply>, also known as
343try to establish and keep a conenction to the given host), C<never> 560"ping-reply"). Other useful values include C<8> (C<echo-request>, a.k.a.
344(nevr initiate a connection to the given host, but accept connections), 561"ping") and C<11> (C<time-exceeded>), but any 8-bit value can be used.
345C<ondemand> (try to establish a connection on the first packet sent, and 562
346take it down after the keepalive interval) or C<disabled> (node is bad, 563=item if-up-data = value
347don't talk to it). 564
565The value specified using this directive will be passed to the C<if-up>
566script in the environment variable C<IFUPDATA>.
348 567
349=item inherit-tos = yes|true|on | no|false|off 568=item inherit-tos = yes|true|on | no|false|off
350 569
351Wether to inherit the TOS settings of packets sent to the tunnel when 570Whether 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 571sending 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 572outgoing tunnel packets will have the same TOS setting as the packets sent
354to the tunnel device, which is usually what you want. 573to the tunnel device, which is usually what you want.
355 574
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 575=item max-retry = positive-number
363 576
364The maximum interval in seconds (default: C<28800>, 8 hours) between 577The maximum interval in seconds (default: C<3600>, one hour) between
365retries to establish a connection to this node. When a connection cannot 578retries to establish a connection to this node. When a connection cannot
366be established, gvpe uses exponential backoff capped at this value. It's 579be 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 580sometimes 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 581connections to routers that usually are stable but sometimes are down, to
369assure quick reconnections. 582assure quick reconnections even after longer downtimes.
583
584=item max-ttl = seconds
585
586Expire packets that couldn't be sent after this many seconds
587(default: C<60>). Gvpe will normally queue packets for a node without an
588active connection, in the hope of establishing a connection soon. This
589value specifies the maximum lifetime a packet will stay in the queue, if a
590packet gets older, it will be thrown away.
591
592=item max-queue = positive-number>=1
593
594The maximum number of packets that will be queued (default: C<512>)
595for this node. If more packets are sent then earlier packets will be
596expired. See C<max-ttl>, above.
597
598=item router-priority = 0 | 1 | positive-number>=2
599
600Sets the router priority of the given node (default: C<0>, disabled).
601
602If some node tries to connect to another node but it doesn't have a
603hostname, it asks a router node for it's IP address. The router node
604chosen is the one with the highest priority larger than C<1> that is
605currently reachable. This is called a I<mediated> connection, as the
606connection itself will still be direct, but it uses another node to
607mediate between the two nodes.
608
609The value C<0> disables routing, that means if the node receives a packet
610not for itself it will not forward it but instead drop it.
611
612The special value C<1> allows other hosts to route through the router
613host, but they will never route through it by default (i.e. the config
614file of another node needs to specify a router priority higher than one
615to choose such a node for routing).
616
617The idea behind this is that some hosts can, if required, bump the
618C<router-priority> setting to higher than C<1> in their local config to
619route through specific hosts. If C<router-priority> is C<0>, then routing
620will be refused, so C<1> serves as a "enable, but do not use by default"
621switch.
622
623Nodes with C<router-priority> set to C<2> or higher will always be forced
624to C<connect> = C<always> (unless they are C<disabled>).
625
626=item tcp-port = port-number
627
628Similar to C<udp-port> (default: C<655>), but sets the TCP port number.
629
630=item udp-port = port-number
631
632Sets the port number used by the UDP protocol (default: C<655>, not
633officially assigned by IANA!).
370 634
371=back 635=back
372 636
373=head1 CONFIG DIRECTORY LAYOUT 637=head1 CONFIG DIRECTORY LAYOUT
374 638
402 666
403gvpe(5), gvpe(8), gvpectrl(8). 667gvpe(5), gvpe(8), gvpectrl(8).
404 668
405=head1 AUTHOR 669=head1 AUTHOR
406 670
407Marc Lehmann <gvpe@plan9.de> 671Marc Lehmann <gvpe@schmorp.de>
408 672

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines