gvpe/doc/gvpe.conf.5.pod

=head1 NAME

gvpe.conf - configuration file for the GNU VPE daemon

=head1 SYNOPSIS

   udp-port = 407
   mtu = 1492
   ifname = vpn0

   node = branch1
   hostname = 1.2.3.4

   node = branch2
   hostname = www.example.net
   udp-port = 500       # this host uses a different udp-port

   node = branch3
   connect = ondemand

=head1 DESCRIPTION

The gvpe config file consists of a series of lines that contain C<variable
= value> pairs. Empty lines are ignored. Comments start with a C<#> and
extend to the end of the line. They can be used on their own lines, or
after any directives. Spaces are allowed before or after the C<=> sign or
after values, but not within the variable names or values themselves.

The only exception to the above is the "on" directive that can prefix any
C<name = value> setting and will only "execute" it on the named node, or
(if the nodename starts with "!") on all nodes except the named one.

   name = value
   on branch1 loglevel = noise
   on !branch2 connect = ondemand

All settings are executed "in order", that is, later settings of the same
variable overwrite earlier ones.

=head1 ANATOMY OF A CONFIG FILE

Usually, a config file starts with global settings (like the udp port to
listen on), followed by node-specific sections that begin with a C<node =
nickname> line.

Every node that is part of the network must have a section that starts
with C<node = nickname>. The number and order of the nodes is important
and must be the same on all hosts. It is not uncommon for node sections to
be completely empty - if the default values are right.

Node-specific settings can be used at any time. If used before the first
node section they will set the default values for all following nodes.

=head1 CONFIG VARIABLES

=head2 GLOBAL SETTINGS

Global settings will affect the behaviour of the running gvpe daemon, that
is, they are in some sense node-specific (config files can set different
values on different nodes using C<on>), but will affect the behaviour of
the gvpe daemon and all connections it creates.

=over 4

=item loglevel = noise|trace|debug|info|notice|warn|error|critical

Set the logging level. Connection established messages are logged at level
C<info>, notable errors are logged with C<error>. Default is C<info>.

=item node = nickname

Not really a config setting but introduces a node section. The nickname is
used to select the right configuration section and must be passed as an
argument to the gvpe daemon.

=item private-key = relative-path-to-key

Sets the path (relative to the config directory) to the private key
(default: C<hostkey>). This is a printf format string so every C<%> must
be doubled. A single C<%s> is replaced by the hostname, so you could
use paths like C<hostkeys/%s> to fetch the files at the location where
C<gvpectrl> puts them.

Since only the private key file of the current node is used and the
private key file should be kept secret per-host to avoid spoofings, it is
not recommended to use this feature.

=item ifpersist = yes|true|on | no|false|off

Should the tun/tap device be made persistent, that is, should the device
stay up even when gvpe exits? Some versions of the tunnel device have
problems sending packets when gvpe is restarted in persistent mode, so
if the connections can be established but you cannot send packets from
the local node, try to set this to C<off> and do an ifconfig down on the
device.

=item ifname = devname

Sets the tun interface name to the given name. The default is OS-specific
and most probably something like C<tun0>.

=item rekey = seconds

Sets the rekeying interval in seconds (default: C<3600>). Connections are
reestablished every C<rekey> seconds.

=item keepalive = seconds

Sets the keepalive probe interval in seconds (default: C<60>). After this
many seconds of inactivity the daemon will start to send keepalive probe
every 5 seconds until it receives a reply from the other end.  If no reply
is received within 30 seconds, the peer is considered unreachable and the
connection is closed.

=item mtu = bytes

Sets the maximum MTU that should be used on outgoing packets (basically
the MTU of the outgoing interface) The daemon will automatically calculate
maximum overhead (e.g. udp header size, encryption blocksize...) and pass
this information to the C<if-up> script.

Recommended values are 1500 (ethernet), 1492 (pppoe), 1472 (pptp).

This value must be the minimum of the mtu values of all hosts.

=item ip-proto = numerical-ip-protocol

Sets the protocol number to be used for the rawip protocol. This is a
global option because all hosts must use the same protocol, and since
there are no port numbers, you cannot easily run more than one gvpe
instance using the same protocol, nor can you share the protocol with
other programs.

The default is 47 (GRE), which has a good chance of tunneling through
firewalls (but note that the rawip protocol is not GRE compatible). Other
common choices are 50 (IPSEC, ESP), 51 (IPSEC, AH), 4 (IPIP tunnels) or 98
(ENCAP, rfc1241)

=item if-up = relative-or-absolute-path

Sets the path of a script that should be called immediately after the
network interface is initialized (but not neccessarily up). The following
environment variables are passed to it (the values are just examples):

=over 4

=item CONFBASE=/etc/gvpe

The configuration base directory.

=item IFNAME=vpn0

The interface to initialize.

=item MTU=1436

The MTU to set the interface to. You can use lower values (if done
consistently on all hosts), but this is usually ineffective.

=item MAC=fe:fd:80:00:00:01

The MAC address to set the interface to. The script *must* set the
interface MAC to this value. You will most likely use one of these:

   ip link set $IFNAME address $MAC mtu $MTU up # GNU/Linux
   ifconfig $IFNAME ether $MAC mtu $MTU up      # FreeBSD

Please see the C<gvpe.osdep(5)> manpage for platform-specific information.

=item IFTYPE=native # or tincd

=item IFSUBTYPE=linux # or freebsd, darwin etc..

The interface type (C<native> or C<tincd>) and the subtype (usually the os
name in lowercase) that this gvpe was configured for. Can be used to select
the correct syntax to use for network-related commands.

=item NODENAME=branch1

The nickname of the current node, as passed to the gvpe daemon.

=item NODEID=1

The numerical node id of the current node. The first node mentioned in the
config file gets ID 1, the second ID 2 and so on.

=back

Here is a simple if-up script:

   #!/bin/sh
   ip link set $IFNAME address $MAC mtu $MTU up
   [ $NODENAME = branch1 ] && ip addr add 10.0.0.1 dev $IFNAME
   [ $NODENAME = branch2 ] && ip addr add 10.1.0.1 dev $IFNAME
   ip route add 10.0.0.0/8 dev $IFNAME

More complicated examples (using routing to reduce arp traffic) can be
found in the etc/ subdirectory of the distribution.

=item node-up = relative-or-absolute-path

Sets a command (default: no script) that should be called whenever a
connection is established (even on rekeying operations). In addition
to the variables passed to C<if-up> scripts, the following environment
variables will be set:

=over 4

=item DESTNODE=branch2

The name of the remote node.

=item DESTID=2

The node id of the remote node.

=item DESTIP=188.13.66.8

The numerical IP address of the remote host (gvpe accepts connections from
everywhere, as long as the other host can authenticate itself).

=item DESTPORT=655 # deprecated

The UDP port used by the other side.

=item STATE=UP

Node-up scripts get called with STATE=UP, node-down scripts get called
with STATE=DOWN.

=back

Here is a nontrivial example that uses nsupdate to update the name => ip
mapping in some dns zone:

   #!/bin/sh
   {
     echo update delete $DESTNODE.lowttl.example.net. a
     echo update add $DESTNODE.lowttl.example.net. 1 in a $DESTIP
     echo   
   } | nsupdate -d -k $CONFBASE:key.example.net.

=item node-down = relative-or-absolute-path

Same as C<node-up>, but gets called whenever a connection is lost.

=item http-proxy-host = hostname/ip

The C<http-proxy-*> family of options are only available if gvpe was
compiled with the C<--enable-http-proxy> option and enable tunneling of
tcp connections through a http proxy server.

C<http-proxy-host> and C<http-proxy-port> should specify the hostname and
port number of the proxy server. See C<http-proxy-loginpw> if your proxy
requires authentication.

Please note that gvpe will still try to resolve all hostnames in the
configuration file, so if you are behind a proxy without access to a dns
server better use numerical IP addresses.

To make best use of this option disable all protocols except tcp in your
config file and make sure your routers (or all other hosts) are listening
on a port that the proxy allows (443, https, is a common choice).

If you have a router, connecting to it will suffice. Otherwise tcp must be
enabled on all hosts.

Example:

   http-proxy-host = proxy.example.com
   http-proxy-port = 3128       # 8080 is another common choice
   http-proxy-auth = schmorp:grumbeere

=item http-proxy-port = proxy-tcp-port

The port where your proxy server listens.

=item http-proxy-auth = login:password

The optional login and password used to authenticate to the proxy server,
seperated by a literal colon (C<:>). Only basic authentication is
currently supported.

=item pid-file = path

The path to the pid file to check and create (Default:

=back

=head2 NODE SPECIFIC SETTINGS

The following settings are node-specific, that is, every node can have
different settings, even within the same gvpe instance. Settings that are
executed before the first node section set the defaults, settings that are
executed within a node section only apply to the given node.

=over 4

=item udp-port = port-number

Sets the port number used by the UDP protocol (default: C<655>, not
officially assigned by IANA!).

=item tcp-port = port-number

Similar to C<udp-port> (default: C<655>), but sets the TCP port number.

=item enable-rawip = yes|true|on | no|false|off

Enable the RAW IPv4 transport using the C<ip-proto> protocol
(default: C<no>). This is the best choice, since the overhead per packet
is only 38 bytes, as opposed to UDP's 58 (or TCP's 60+).

=item enable-udp = yes|true|on | no|false|off

Enable the UDPv4 transport using the C<udp-port> port (default: C<no>,
unless no other protocol is enabled for a node, in which case this
protocol is enabled automatically). This is a good general choice since
UDP tunnels well through many firewalls.

NOTE: Please specify C<enable-udp = yes> if you want t use it even though
it might get switched on automatically, as some future version might
default to another default protocol.

=item enable-tcp = yes|true|on | no|false|off

Enable the TCPv4 transport using the C<tcp-port> port
(default: C<no>). Support for this horribly unsuitable protocol is only
available when gvpe was compiled using the C<--enable-tcp> option. Never
use this transport unless you really must, it is horribly ineffiecent and
resource-intensive compared to the other transports.

=item router-priority = 0 | 1 | positive-number>2

Sets the router priority of the given host (default: C<0>, disabled). If
some host tries to connect to another host without a hostname, it asks
the router host for it's IP address. The router host is the one with the
highest priority larger than C<1> that is currently reachable.

Make sure all hosts always connect (C<connect = always>) to the router
hosts, otherwise connecting to them might be impossible.

The special value C<1> allows other hosts to route through the router
host, but they will never route through it by default. The value C<0>
disables routing. The idea behind this is that some hosts can, if
required, bump the C<router-priority> setting to higher than C<1> in their
local config to route through specific hosts. If C<router-priority> is
C<0>, then routing will be refused, so C<1> serves as a "enable, but do
not use by default" switch.

=item connect = ondemand | never | always | disabled

Sets the connect mode (default: C<always>). It can be C<always> (always
try to establish and keep a connection to the given host), C<never>
(never initiate a connection to the given host, but accept connections),
C<ondemand> (try to establish a connection on the first packet sent, and
take it down after the keepalive interval) or C<disabled> (node is bad,
don't talk to it).

=item inherit-tos = yes|true|on | no|false|off

Wether to inherit the TOS settings of packets sent to the tunnel when
sending packets to this node (default: C<yes>). If set to C<yes> then
outgoing tunnel packets will have the same TOS setting as the packets sent
to the tunnel device, which is usually what you want.

=item compress = yes|true|on | no|false|off

Wether to compress data packets sent to this host (default: C<yes>).
Compression is really cheap even on slow computers and has no size
overhead at all, so enabling this is a good idea.

=item max-retry = positive-number

The maximum interval in seconds (default: C<28800>, 8 hours) between
retries to establish a connection to this node. When a connection cannot
be established, gvpe uses exponential backoff capped at this value. It's
sometimes useful to set this to a much lower value (e.g. C<120>) on
connections to routers that usually are stable but sometimes are down, to
assure quick reconnections.

=back

=head1 CONFIG DIRECTORY LAYOUT

The default (or recommended) directory layout for the config directory is:

=over 4

=item X<gvpe.conf>

The config file.

=item X<if-up>

The if-up script

=item X<node-up>, X<node-down>

If used the node up or node-down scripts.

=item X<hostkey>

The private key (taken from C<hostkeys/nodename>) of the current host.

=item X<pubkey/nodename>

The public keys of the other nodes, one file per node.

=back

=head1 SEE ALSO

gvpe(5), gvpe(8), gvpectrl(8).

=head1 AUTHOR

Marc Lehmann <gvpe@plan9.de>

Revision:	1.5
Committed:	Tue Mar 1 06:27:20 2005 UTC (19 years, 2 months ago) by pcg
Branch:	MAIN
Changes since 1.4:	+8 -7 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	pcg	1.1	=head1 NAME
2
3			gvpe.conf - configuration file for the GNU VPE daemon
4
5			=head1 SYNOPSIS
6
7			udp-port = 407
8			mtu = 1492
9			ifname = vpn0
10
11			node = branch1
12			hostname = 1.2.3.4
13
14			node = branch2
15			hostname = www.example.net
16			udp-port = 500 # this host uses a different udp-port
17
18			node = branch3
19			connect = ondemand
20
21			=head1 DESCRIPTION
22
23			The gvpe config file consists of a series of lines that contain C<variable
24			= value> pairs. Empty lines are ignored. Comments start with a C<#> and
25			extend to the end of the line. They can be used on their own lines, or
26			after any directives. Spaces are allowed before or after the C<=> sign or
27			after values, but not within the variable names or values themselves.
28
29			The only exception to the above is the "on" directive that can prefix any
30			C<name = value> setting and will only "execute" it on the named node, or
31			(if the nodename starts with "!") on all nodes except the named one.
32
33			name = value
34			on branch1 loglevel = noise
35			on !branch2 connect = ondemand
36
37			All settings are executed "in order", that is, later settings of the same
38			variable overwrite earlier ones.
39
40			=head1 ANATOMY OF A CONFIG FILE
41
42			Usually, a config file starts with global settings (like the udp port to
43			listen on), followed by node-specific sections that begin with a C<node =
44			nickname> line.
45
46			Every node that is part of the network must have a section that starts
47			with C<node = nickname>. The number and order of the nodes is important
48			and must be the same on all hosts. It is not uncommon for node sections to
49			be completely empty - if the default values are right.
50
51			Node-specific settings can be used at any time. If used before the first
52			node section they will set the default values for all following nodes.
53
54			=head1 CONFIG VARIABLES
55
56			=head2 GLOBAL SETTINGS
57
58			Global settings will affect the behaviour of the running gvpe daemon, that
59			is, they are in some sense node-specific (config files can set different
60			values on different nodes using C<on>), but will affect the behaviour of
61			the gvpe daemon and all connections it creates.
62
63			=over 4
64
65			=item loglevel = noise\|trace\|debug\|info\|notice\|warn\|error\|critical
66
67			Set the logging level. Connection established messages are logged at level
68			C<info>, notable errors are logged with C<error>. Default is C<info>.
69
70			=item node = nickname
71
72			Not really a config setting but introduces a node section. The nickname is
73			used to select the right configuration section and must be passed as an
74			argument to the gvpe daemon.
75
76			=item private-key = relative-path-to-key
77
78			Sets the path (relative to the config directory) to the private key
79			(default: C<hostkey>). This is a printf format string so every C<%> must
80			be doubled. A single C<%s> is replaced by the hostname, so you could
81			use paths like C<hostkeys/%s> to fetch the files at the location where
82			C<gvpectrl> puts them.
83
84			Since only the private key file of the current node is used and the
85			private key file should be kept secret per-host to avoid spoofings, it is
86			not recommended to use this feature.
87
88			=item ifpersist = yes\|true\|on \| no\|false\|off
89
90			Should the tun/tap device be made persistent, that is, should the device
91			stay up even when gvpe exits? Some versions of the tunnel device have
92			problems sending packets when gvpe is restarted in persistent mode, so
93			if the connections can be established but you cannot send packets from
94			the local node, try to set this to C<off> and do an ifconfig down on the
95			device.
96
97			=item ifname = devname
98
99			Sets the tun interface name to the given name. The default is OS-specific
100			and most probably something like C<tun0>.
101
102			=item rekey = seconds
103
104			Sets the rekeying interval in seconds (default: C<3600>). Connections are
105			reestablished every C<rekey> seconds.
106
107			=item keepalive = seconds
108
109			Sets the keepalive probe interval in seconds (default: C<60>). After this
110			many seconds of inactivity the daemon will start to send keepalive probe
111			every 5 seconds until it receives a reply from the other end. If no reply
112			is received within 30 seconds, the peer is considered unreachable and the
113			connection is closed.
114
115			=item mtu = bytes
116
117			Sets the maximum MTU that should be used on outgoing packets (basically
118			the MTU of the outgoing interface) The daemon will automatically calculate
119			maximum overhead (e.g. udp header size, encryption blocksize...) and pass
120			this information to the C<if-up> script.
121
122			Recommended values are 1500 (ethernet), 1492 (pppoe), 1472 (pptp).
123
124			This value must be the minimum of the mtu values of all hosts.
125
126			=item ip-proto = numerical-ip-protocol
127
128			Sets the protocol number to be used for the rawip protocol. This is a
129			global option because all hosts must use the same protocol, and since
130			there are no port numbers, you cannot easily run more than one gvpe
131			instance using the same protocol, nor can you share the protocol with
132			other programs.
133
134			The default is 47 (GRE), which has a good chance of tunneling through
135			firewalls (but note that the rawip protocol is not GRE compatible). Other
136			common choices are 50 (IPSEC, ESP), 51 (IPSEC, AH), 4 (IPIP tunnels) or 98
137			(ENCAP, rfc1241)
138
139			=item if-up = relative-or-absolute-path
140
141			Sets the path of a script that should be called immediately after the
142			network interface is initialized (but not neccessarily up). The following
143			environment variables are passed to it (the values are just examples):
144
145			=over 4
146
147			=item CONFBASE=/etc/gvpe
148
149			The configuration base directory.
150
151			=item IFNAME=vpn0
152
153			The interface to initialize.
154
155			=item MTU=1436
156
157			The MTU to set the interface to. You can use lower values (if done
158			consistently on all hosts), but this is usually ineffective.
159
160			=item MAC=fe:fd:80:00:00:01
161
162			The MAC address to set the interface to. The script must set the
163			interface MAC to this value. You will most likely use one of these:
164
165			ip link set $IFNAME address $MAC mtu $MTU up # GNU/Linux
166			ifconfig $IFNAME ether $MAC mtu $MTU up # FreeBSD
167
168			Please see the C<gvpe.osdep(5)> manpage for platform-specific information.
169
170			=item IFTYPE=native # or tincd
171
172			=item IFSUBTYPE=linux # or freebsd, darwin etc..
173
174			The interface type (C<native> or C<tincd>) and the subtype (usually the os
175			name in lowercase) that this gvpe was configured for. Can be used to select
176			the correct syntax to use for network-related commands.
177
178			=item NODENAME=branch1
179
180			The nickname of the current node, as passed to the gvpe daemon.
181
182			=item NODEID=1
183
184			The numerical node id of the current node. The first node mentioned in the
185			config file gets ID 1, the second ID 2 and so on.
186
187			=back
188
189			Here is a simple if-up script:
190
191			#!/bin/sh
192			ip link set $IFNAME address $MAC mtu $MTU up
193			[ $NODENAME = branch1 ] && ip addr add 10.0.0.1 dev $IFNAME
194			[ $NODENAME = branch2 ] && ip addr add 10.1.0.1 dev $IFNAME
195			ip route add 10.0.0.0/8 dev $IFNAME
196
197			More complicated examples (using routing to reduce arp traffic) can be
198			found in the etc/ subdirectory of the distribution.
199
200			=item node-up = relative-or-absolute-path
201
202			Sets a command (default: no script) that should be called whenever a
203			connection is established (even on rekeying operations). In addition
204			to the variables passed to C<if-up> scripts, the following environment
205			variables will be set:
206
207			=over 4
208
209			=item DESTNODE=branch2
210
211			The name of the remote node.
212
213			=item DESTID=2
214
215			The node id of the remote node.
216
217			=item DESTIP=188.13.66.8
218
219			The numerical IP address of the remote host (gvpe accepts connections from
220			everywhere, as long as the other host can authenticate itself).
221
222			=item DESTPORT=655 # deprecated
223
224			The UDP port used by the other side.
225
226			=item STATE=UP
227
228			Node-up scripts get called with STATE=UP, node-down scripts get called
229			with STATE=DOWN.
230
231			=back
232
233			Here is a nontrivial example that uses nsupdate to update the name => ip
234			mapping in some dns zone:
235
236			#!/bin/sh
237			{
238			echo update delete $DESTNODE.lowttl.example.net. a
239			echo update add $DESTNODE.lowttl.example.net. 1 in a $DESTIP
240			echo
241			} \| nsupdate -d -k $CONFBASE:key.example.net.
242
243			=item node-down = relative-or-absolute-path
244
245			Same as C<node-up>, but gets called whenever a connection is lost.
246
247			=item http-proxy-host = hostname/ip
248
249			The C<http-proxy-*> family of options are only available if gvpe was
250			compiled with the C<--enable-http-proxy> option and enable tunneling of
251			tcp connections through a http proxy server.
252
253			C<http-proxy-host> and C<http-proxy-port> should specify the hostname and
254			port number of the proxy server. See C<http-proxy-loginpw> if your proxy
255			requires authentication.
256
257			Please note that gvpe will still try to resolve all hostnames in the
258			configuration file, so if you are behind a proxy without access to a dns
259			server better use numerical IP addresses.
260
261			To make best use of this option disable all protocols except tcp in your
262			config file and make sure your routers (or all other hosts) are listening
263			on a port that the proxy allows (443, https, is a common choice).
264
265			If you have a router, connecting to it will suffice. Otherwise tcp must be
266			enabled on all hosts.
267
268			Example:
269
270			http-proxy-host = proxy.example.com
271			http-proxy-port = 3128 # 8080 is another common choice
272			http-proxy-auth = schmorp:grumbeere
273
274			=item http-proxy-port = proxy-tcp-port
275
276			The port where your proxy server listens.
277
278			=item http-proxy-auth = login:password
279
280			The optional login and password used to authenticate to the proxy server,
281			seperated by a literal colon (C<:>). Only basic authentication is
282			currently supported.
283
284			=item pid-file = path
285
286			The path to the pid file to check and create (Default:
287
288			=back
289
290			=head2 NODE SPECIFIC SETTINGS
291
292			The following settings are node-specific, that is, every node can have
293			different settings, even within the same gvpe instance. Settings that are
294			executed before the first node section set the defaults, settings that are
295			executed within a node section only apply to the given node.
296
297			=over 4
298
299			=item udp-port = port-number
300
301			Sets the port number used by the UDP protocol (default: C<655>, not
302			officially assigned by IANA!).
303
304			=item tcp-port = port-number
305
306			Similar to C<udp-port> (default: C<655>), but sets the TCP port number.
307
308			=item enable-rawip = yes\|true\|on \| no\|false\|off
309
310			Enable the RAW IPv4 transport using the C<ip-proto> protocol
311			(default: C<no>). This is the best choice, since the overhead per packet
312			is only 38 bytes, as opposed to UDP's 58 (or TCP's 60+).
313
314			=item enable-udp = yes\|true\|on \| no\|false\|off
315
316	pcg	1.5	Enable the UDPv4 transport using the C<udp-port> port (default: C<no>,
317			unless no other protocol is enabled for a node, in which case this
318			protocol is enabled automatically). This is a good general choice since
319			UDP tunnels well through many firewalls.
320
321			NOTE: Please specify C<enable-udp = yes> if you want t use it even though
322			it might get switched on automatically, as some future version might
323			default to another default protocol.
324	pcg	1.1
325			=item enable-tcp = yes\|true\|on \| no\|false\|off
326
327			Enable the TCPv4 transport using the C<tcp-port> port
328			(default: C<no>). Support for this horribly unsuitable protocol is only
329			available when gvpe was compiled using the C<--enable-tcp> option. Never
330			use this transport unless you really must, it is horribly ineffiecent and
331			resource-intensive compared to the other transports.
332
333	pcg	1.2	=item router-priority = 0 \| 1 \| positive-number>2
334	pcg	1.1
335			Sets the router priority of the given host (default: C<0>, disabled). If
336			some host tries to connect to another host without a hostname, it asks
337			the router host for it's IP address. The router host is the one with the
338	pcg	1.2	highest priority larger than C<1> that is currently reachable.
339	pcg	1.1
340	pcg	1.2	Make sure all hosts always connect (C<connect = always>) to the router
341			hosts, otherwise connecting to them might be impossible.
342
343			The special value C<1> allows other hosts to route through the router
344			host, but they will never route through it by default. The value C<0>
345			disables routing. The idea behind this is that some hosts can, if
346			required, bump the C<router-priority> setting to higher than C<1> in their
347			local config to route through specific hosts. If C<router-priority> is
348			C<0>, then routing will be refused, so C<1> serves as a "enable, but do
349			not use by default" switch.
350
351			=item connect = ondemand \| never \| always \| disabled
352	pcg	1.1
353			Sets the connect mode (default: C<always>). It can be C<always> (always
354	pcg	1.2	try to establish and keep a connection to the given host), C<never>
355	pcg	1.3	(never initiate a connection to the given host, but accept connections),
356	pcg	1.1	C<ondemand> (try to establish a connection on the first packet sent, and
357			take it down after the keepalive interval) or C<disabled> (node is bad,
358			don't talk to it).
359
360			=item inherit-tos = yes\|true\|on \| no\|false\|off
361
362			Wether to inherit the TOS settings of packets sent to the tunnel when
363			sending packets to this node (default: C<yes>). If set to C<yes> then
364			outgoing tunnel packets will have the same TOS setting as the packets sent
365			to the tunnel device, which is usually what you want.
366
367			=item compress = yes\|true\|on \| no\|false\|off
368
369			Wether to compress data packets sent to this host (default: C<yes>).
370			Compression is really cheap even on slow computers and has no size
371			overhead at all, so enabling this is a good idea.
372
373			=item max-retry = positive-number
374
375			The maximum interval in seconds (default: C<28800>, 8 hours) between
376			retries to establish a connection to this node. When a connection cannot
377			be established, gvpe uses exponential backoff capped at this value. It's
378			sometimes useful to set this to a much lower value (e.g. C<120>) on
379			connections to routers that usually are stable but sometimes are down, to
380			assure quick reconnections.
381
382			=back
383
384			=head1 CONFIG DIRECTORY LAYOUT
385
386			The default (or recommended) directory layout for the config directory is:
387
388			=over 4
389
390	pcg	1.4	=item X<gvpe.conf>
391	pcg	1.1
392			The config file.
393
394	pcg	1.4	=item X<if-up>
395	pcg	1.1
396			The if-up script
397
398	pcg	1.4	=item X<node-up>, X<node-down>
399	pcg	1.1
400			If used the node up or node-down scripts.
401
402	pcg	1.4	=item X<hostkey>
403	pcg	1.1
404			The private key (taken from C<hostkeys/nodename>) of the current host.
405
406	pcg	1.4	=item X<pubkey/nodename>
407	pcg	1.1
408			The public keys of the other nodes, one file per node.
409
410			=back
411
412			=head1 SEE ALSO
413
414			gvpe(5), gvpe(8), gvpectrl(8).
415
416			=head1 AUTHOR
417
418			Marc Lehmann <gvpe@plan9.de>
419