gvpe/doc/gvpe.conf.5.pod

=head1 NAME

gvpe.conf - configuration file for the GNU VPE daemon

=head1 SYNOPSIS

   enable-udp = yes
   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<yes>,
but this will change!). This is a good general choice since UDP tunnels
well through many firewalls.

NOTE: Please specify C<enable-udp = yes> even though it is the default, as
some future version will have all protocols disabled by default.

=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:	1.4
Committed:	Thu Jan 27 06:16:16 2005 UTC (19 years, 3 months ago) by pcg
Branch:	MAIN
CVS Tags:	rel-1_7
Changes since 1.3:	+5 -5 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			enable-udp = yes
8			udp-port = 407
9			mtu = 1492
10			ifname = vpn0
11
12			node = branch1
13			hostname = 1.2.3.4
14
15			node = branch2
16			hostname = www.example.net
17			udp-port = 500 # this host uses a different udp-port
18
19			node = branch3
20			connect = ondemand
21
22			=head1 DESCRIPTION
23
24			The 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
26			extend to the end of the line. They can be used on their own lines, or
27			after any directives. Spaces are allowed before or after the C<=> sign or
28			after values, but not within the variable names or values themselves.
29
30			The only exception to the above is the "on" directive that can prefix any
31			C<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.
33
34			name = value
35			on branch1 loglevel = noise
36			on !branch2 connect = ondemand
37
38			All settings are executed "in order", that is, later settings of the same
39			variable overwrite earlier ones.
40
41			=head1 ANATOMY OF A CONFIG FILE
42
43			Usually, a config file starts with global settings (like the udp port to
44			listen on), followed by node-specific sections that begin with a C<node =
45			nickname> line.
46
47			Every node that is part of the network must have a section that starts
48			with C<node = nickname>. The number and order of the nodes is important
49			and must be the same on all hosts. It is not uncommon for node sections to
50			be completely empty - if the default values are right.
51
52			Node-specific settings can be used at any time. If used before the first
53			node section they will set the default values for all following nodes.
54
55			=head1 CONFIG VARIABLES
56
57			=head2 GLOBAL SETTINGS
58
59			Global settings will affect the behaviour of the running gvpe daemon, that
60			is, they are in some sense node-specific (config files can set different
61			values on different nodes using C<on>), but will affect the behaviour of
62			the gvpe daemon and all connections it creates.
63
64			=over 4
65
66			=item loglevel = noise\|trace\|debug\|info\|notice\|warn\|error\|critical
67
68			Set the logging level. Connection established messages are logged at level
69			C<info>, notable errors are logged with C<error>. Default is C<info>.
70
71			=item node = nickname
72
73			Not really a config setting but introduces a node section. The nickname is
74			used to select the right configuration section and must be passed as an
75			argument to the gvpe daemon.
76
77			=item private-key = relative-path-to-key
78
79			Sets the path (relative to the config directory) to the private key
80			(default: C<hostkey>). This is a printf format string so every C<%> must
81			be doubled. A single C<%s> is replaced by the hostname, so you could
82			use paths like C<hostkeys/%s> to fetch the files at the location where
83			C<gvpectrl> puts them.
84
85			Since only the private key file of the current node is used and the
86			private key file should be kept secret per-host to avoid spoofings, it is
87			not recommended to use this feature.
88
89			=item ifpersist = yes\|true\|on \| no\|false\|off
90
91			Should the tun/tap device be made persistent, that is, should the device
92			stay up even when gvpe exits? Some versions of the tunnel device have
93			problems sending packets when gvpe is restarted in persistent mode, so
94			if the connections can be established but you cannot send packets from
95			the local node, try to set this to C<off> and do an ifconfig down on the
96			device.
97
98			=item ifname = devname
99
100			Sets the tun interface name to the given name. The default is OS-specific
101			and most probably something like C<tun0>.
102
103			=item rekey = seconds
104
105			Sets the rekeying interval in seconds (default: C<3600>). Connections are
106			reestablished every C<rekey> seconds.
107
108			=item keepalive = seconds
109
110			Sets the keepalive probe interval in seconds (default: C<60>). After this
111			many seconds of inactivity the daemon will start to send keepalive probe
112			every 5 seconds until it receives a reply from the other end. If no reply
113			is received within 30 seconds, the peer is considered unreachable and the
114			connection is closed.
115
116			=item mtu = bytes
117
118			Sets the maximum MTU that should be used on outgoing packets (basically
119			the MTU of the outgoing interface) The daemon will automatically calculate
120			maximum overhead (e.g. udp header size, encryption blocksize...) and pass
121			this information to the C<if-up> script.
122
123			Recommended values are 1500 (ethernet), 1492 (pppoe), 1472 (pptp).
124
125			This value must be the minimum of the mtu values of all hosts.
126
127			=item ip-proto = numerical-ip-protocol
128
129			Sets the protocol number to be used for the rawip protocol. This is a
130			global option because all hosts must use the same protocol, and since
131			there are no port numbers, you cannot easily run more than one gvpe
132			instance using the same protocol, nor can you share the protocol with
133			other programs.
134
135			The default is 47 (GRE), which has a good chance of tunneling through
136			firewalls (but note that the rawip protocol is not GRE compatible). Other
137			common choices are 50 (IPSEC, ESP), 51 (IPSEC, AH), 4 (IPIP tunnels) or 98
138			(ENCAP, rfc1241)
139
140			=item if-up = relative-or-absolute-path
141
142			Sets the path of a script that should be called immediately after the
143			network interface is initialized (but not neccessarily up). The following
144			environment variables are passed to it (the values are just examples):
145
146			=over 4
147
148			=item CONFBASE=/etc/gvpe
149
150			The configuration base directory.
151
152			=item IFNAME=vpn0
153
154			The interface to initialize.
155
156			=item MTU=1436
157
158			The MTU to set the interface to. You can use lower values (if done
159			consistently on all hosts), but this is usually ineffective.
160
161			=item MAC=fe:fd:80:00:00:01
162
163			The MAC address to set the interface to. The script must set the
164			interface 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
169			Please 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
175			The interface type (C<native> or C<tincd>) and the subtype (usually the os
176			name in lowercase) that this gvpe was configured for. Can be used to select
177			the correct syntax to use for network-related commands.
178
179			=item NODENAME=branch1
180
181			The nickname of the current node, as passed to the gvpe daemon.
182
183			=item NODEID=1
184
185			The numerical node id of the current node. The first node mentioned in the
186			config file gets ID 1, the second ID 2 and so on.
187
188			=back
189
190			Here 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
198			More complicated examples (using routing to reduce arp traffic) can be
199			found in the etc/ subdirectory of the distribution.
200
201			=item node-up = relative-or-absolute-path
202
203			Sets a command (default: no script) that should be called whenever a
204			connection is established (even on rekeying operations). In addition
205			to the variables passed to C<if-up> scripts, the following environment
206			variables will be set:
207
208			=over 4
209
210			=item DESTNODE=branch2
211
212			The name of the remote node.
213
214			=item DESTID=2
215
216			The node id of the remote node.
217
218			=item DESTIP=188.13.66.8
219
220			The numerical IP address of the remote host (gvpe accepts connections from
221			everywhere, as long as the other host can authenticate itself).
222
223			=item DESTPORT=655 # deprecated
224
225			The UDP port used by the other side.
226
227			=item STATE=UP
228
229			Node-up scripts get called with STATE=UP, node-down scripts get called
230			with STATE=DOWN.
231
232			=back
233
234			Here is a nontrivial example that uses nsupdate to update the name => ip
235			mapping in some dns zone:
236
237			#!/bin/sh
238			{
239			echo update delete $DESTNODE.lowttl.example.net. a
240			echo update add $DESTNODE.lowttl.example.net. 1 in a $DESTIP
241			echo
242			} \| nsupdate -d -k $CONFBASE:key.example.net.
243
244			=item node-down = relative-or-absolute-path
245
246			Same as C<node-up>, but gets called whenever a connection is lost.
247
248			=item http-proxy-host = hostname/ip
249
250			The C<http-proxy-*> family of options are only available if gvpe was
251			compiled with the C<--enable-http-proxy> option and enable tunneling of
252			tcp connections through a http proxy server.
253
254			C<http-proxy-host> and C<http-proxy-port> should specify the hostname and
255			port number of the proxy server. See C<http-proxy-loginpw> if your proxy
256			requires authentication.
257
258			Please note that gvpe will still try to resolve all hostnames in the
259			configuration file, so if you are behind a proxy without access to a dns
260			server better use numerical IP addresses.
261
262			To make best use of this option disable all protocols except tcp in your
263			config file and make sure your routers (or all other hosts) are listening
264			on a port that the proxy allows (443, https, is a common choice).
265
266			If you have a router, connecting to it will suffice. Otherwise tcp must be
267			enabled on all hosts.
268
269			Example:
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
277			The port where your proxy server listens.
278
279			=item http-proxy-auth = login:password
280
281			The optional login and password used to authenticate to the proxy server,
282			seperated by a literal colon (C<:>). Only basic authentication is
283			currently supported.
284
285			=item pid-file = path
286
287			The path to the pid file to check and create (Default:
288
289			=back
290
291			=head2 NODE SPECIFIC SETTINGS
292
293			The following settings are node-specific, that is, every node can have
294			different settings, even within the same gvpe instance. Settings that are
295			executed before the first node section set the defaults, settings that are
296			executed within a node section only apply to the given node.
297
298			=over 4
299
300			=item udp-port = port-number
301
302			Sets the port number used by the UDP protocol (default: C<655>, not
303			officially assigned by IANA!).
304
305			=item tcp-port = port-number
306
307			Similar to C<udp-port> (default: C<655>), but sets the TCP port number.
308
309			=item enable-rawip = yes\|true\|on \| no\|false\|off
310
311			Enable the RAW IPv4 transport using the C<ip-proto> protocol
312			(default: C<no>). This is the best choice, since the overhead per packet
313			is only 38 bytes, as opposed to UDP's 58 (or TCP's 60+).
314
315			=item enable-udp = yes\|true\|on \| no\|false\|off
316
317			Enable the UDPv4 transport using the C<udp-port> port (default: C<yes>,
318			but this will change!). This is a good general choice since UDP tunnels
319			well through many firewalls.
320
321			NOTE: Please specify C<enable-udp = yes> even though it is the default, as
322			some future version will have all protocols disabled by default.
323
324			=item enable-tcp = yes\|true\|on \| no\|false\|off
325
326			Enable the TCPv4 transport using the C<tcp-port> port
327			(default: C<no>). Support for this horribly unsuitable protocol is only
328			available when gvpe was compiled using the C<--enable-tcp> option. Never
329			use this transport unless you really must, it is horribly ineffiecent and
330			resource-intensive compared to the other transports.
331
332	pcg	1.2	=item router-priority = 0 \| 1 \| positive-number>2
333	pcg	1.1
334			Sets the router priority of the given host (default: C<0>, disabled). If
335			some host tries to connect to another host without a hostname, it asks
336			the router host for it's IP address. The router host is the one with the
337	pcg	1.2	highest priority larger than C<1> that is currently reachable.
338	pcg	1.1
339	pcg	1.2	Make sure all hosts always connect (C<connect = always>) to the router
340			hosts, otherwise connecting to them might be impossible.
341
342			The special value C<1> allows other hosts to route through the router
343			host, but they will never route through it by default. The value C<0>
344			disables routing. The idea behind this is that some hosts can, if
345			required, bump the C<router-priority> setting to higher than C<1> in their
346			local config to route through specific hosts. If C<router-priority> is
347			C<0>, then routing will be refused, so C<1> serves as a "enable, but do
348			not use by default" switch.
349
350			=item connect = ondemand \| never \| always \| disabled
351	pcg	1.1
352			Sets the connect mode (default: C<always>). It can be C<always> (always
353	pcg	1.2	try to establish and keep a connection to the given host), C<never>
354	pcg	1.3	(never initiate a connection to the given host, but accept connections),
355	pcg	1.1	C<ondemand> (try to establish a connection on the first packet sent, and
356			take it down after the keepalive interval) or C<disabled> (node is bad,
357			don't talk to it).
358
359			=item inherit-tos = yes\|true\|on \| no\|false\|off
360
361			Wether to inherit the TOS settings of packets sent to the tunnel when
362			sending packets to this node (default: C<yes>). If set to C<yes> then
363			outgoing tunnel packets will have the same TOS setting as the packets sent
364			to the tunnel device, which is usually what you want.
365
366			=item compress = yes\|true\|on \| no\|false\|off
367
368			Wether to compress data packets sent to this host (default: C<yes>).
369			Compression is really cheap even on slow computers and has no size
370			overhead at all, so enabling this is a good idea.
371
372			=item max-retry = positive-number
373
374			The maximum interval in seconds (default: C<28800>, 8 hours) between
375			retries to establish a connection to this node. When a connection cannot
376			be established, gvpe uses exponential backoff capped at this value. It's
377			sometimes useful to set this to a much lower value (e.g. C<120>) on
378			connections to routers that usually are stable but sometimes are down, to
379			assure quick reconnections.
380
381			=back
382
383			=head1 CONFIG DIRECTORY LAYOUT
384
385			The default (or recommended) directory layout for the config directory is:
386
387			=over 4
388
389	pcg	1.4	=item X<gvpe.conf>
390	pcg	1.1
391			The config file.
392
393	pcg	1.4	=item X<if-up>
394	pcg	1.1
395			The if-up script
396
397	pcg	1.4	=item X<node-up>, X<node-down>
398	pcg	1.1
399			If used the node up or node-down scripts.
400
401	pcg	1.4	=item X<hostkey>
402	pcg	1.1
403			The private key (taken from C<hostkeys/nodename>) of the current host.
404
405	pcg	1.4	=item X<pubkey/nodename>
406	pcg	1.1
407			The public keys of the other nodes, one file per node.
408
409			=back
410
411			=head1 SEE ALSO
412
413			gvpe(5), gvpe(8), gvpectrl(8).
414
415			=head1 AUTHOR
416
417			Marc Lehmann <gvpe@plan9.de>
418