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 dns-forw-host = hostname/ip

The dns server to forward dns requests to for the DNS tunnel protocol
(default: C<127.0.0.1>, changing it is highly recommended).

=item dns-forw-port = port-number

The port where the C<dns-forw-host> is to be contacted (default: C<53>,
which is fine in most cases).

=item dns-max-outstanding = integer-number-of-requests

The maximum number of outstanding DNS transport requests
(default: C<100>). GVPE will never issue more requests then the given
limit without receiving replies. In heavily overloaded situations it might
help to set this to a low number (e.g. C<3> or even C<1>) to limit the
number of parallel requests.

The default should be working ok for most links.

=item dns-overlap-factor = float

The DNS transport uses the minimum request latency (B<min_latency>) seen
during a connection as it's timing base. This factor (default: C<0.5>,
must be > 0) is multiplied by B<min_latency> to get the maximum sending
rate (= minimum send interval), i.e. a factor of C<1> means that a new
request might be generated every B<min_latency> seconds, which means on
average there should only ever be one outstanding request.  A factor of
C<0.5> means that GVPE will send requests twice as often as the minimum
latency measured.

For congested or picky dns forwarders you could use a value nearer to or
exceeding C<1>.

The default should be working ok for most links.

=item dns-send-interval = send-interval-in-seconds

The minimum send interval (= maximum rate) that the DNS transport will
use to send new DNS requests. GVPE will not exceed this rate even when
the latency is very low. The default is C<0.01>, which means GVPE will
not send more than 100 DNS requests per connection per second. For
high-bandwidth links you could go lower, e.g. to C<0.001> or so. For
congested or rate-limited links, you might want to go higher, say C<0.1>,
C<0.2> or even higher.

The default should be working ok for most links.

=item dns-timeout-factor = float

Factor to multiply the C<min_latency> (see C<dns-overlap-factor>) by to
get request timeouts. The default of C<8> means that the DNS transport
will resend the request when no reply has been received for longer than
eight times the minimum (= expected) latency, assuming the request or
reply has been lost.

For congested links a higher value might be necessary (e.g. C<30>). If the
link is very stable lower values (e.g. C<2>) might work nicely. Values
near or below C<1> makes no sense whatsoever.

The default should be working ok for most links.

=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 ifname = devname

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

=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 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 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 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 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 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 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 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 pid-file = path

The path to the pid file to check and create
(default: C<LOCALSTATEDIR/run/gvpe.pid>).

=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 rekey = seconds

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

=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 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 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 dns-domain = domain-suffix

The DNS domain suffix that points to the DNS tunnel server for this node.

The domain must point to a NS record that points to the I<dns-hostname>,
i.e.

   dns-domainname = tunnel.example.net
   dns-hostname   = tunnel-server.example.net

Corresponds to the following DNS entries in the C<example.net> domain:

   tunnel.example.net.         NS tunnel-server.example.net.
   tunnel-server.example.net.  A  13.13.13.13

=item dns-hostname = hostname/ip

The address to bind the DNS tunnel socket to, similar to the C<hostname>,
but for the DNS tunnel protocol only. Default: C<0.0.0.0>, but that might
change.

=item dns-port = port-number

The port to bind the DNS tunnel socket to. Must be C<53> on DNS tunnel servers.

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

See gvpe.protocol(7) for a description of the DNS transport
protocol. Avoid this protocol if you can.

Enable the DNS tunneling protocol on this node, either as server or as
client. Support for this transport protocol is only available when gvpe
was compiled using the C<--enable-dns> option.

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

See gvpe.protocol(7) for a description of the ICMP transport protocol.

Enable the ICMP transport using icmp packets of type C<icmp-type> on this
node.

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

See gvpe.protocol(7) for a description of the RAW IP transport protocol.

Enable the RAW IPv4 transport using the C<ip-proto> protocol
(default: C<no>).

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

See gvpe.protocol(7) for a description of the TCP transport protocol.

Enable the TCPv4 transport using the C<tcp-port> port
(default: C<no>). Support for this transport protocol is only available
when gvpe was compiled using the C<--enable-tcp> option.

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

See gvpe.protocol(7) for a description of the UDP transport protocol.

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).

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 icmp-type = integer

Sets the type value to be used for outgoing (and incoming) packets sent
via the ICMP transport.

The default is C<0> (which is C<echo-reply>, also known as
"ping-replies"). Other useful values include C<8> (C<echo-request>, a.k.a.
"ping") and C<11> (C<time-exceeded>), but any 8-bit value can be used.

=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 max-retry = positive-number

The maximum interval in seconds (default: C<3600>, one hour) 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 even after longer downtimes.

=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 tcp-port = port-number

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

=item udp-port = port-number

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

=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:	1.12
Committed:	Wed Mar 23 17:03:58 2005 UTC (19 years, 2 months ago) by pcg
Branch:	MAIN
Changes since 1.11:	+52 -0 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	pcg	1.6	=item dns-forw-host = hostname/ip
66	pcg	1.1
67	pcg	1.6	The dns server to forward dns requests to for the DNS tunnel protocol
68			(default: C<127.0.0.1>, changing it is highly recommended).
69	pcg	1.1
70	pcg	1.6	=item dns-forw-port = port-number
71	pcg	1.1
72	pcg	1.6	The port where the C<dns-forw-host> is to be contacted (default: C<53>,
73			which is fine in most cases).
74	pcg	1.1
75	pcg	1.12	=item dns-max-outstanding = integer-number-of-requests
76
77			The maximum number of outstanding DNS transport requests
78			(default: C<100>). GVPE will never issue more requests then the given
79			limit without receiving replies. In heavily overloaded situations it might
80			help to set this to a low number (e.g. C<3> or even C<1>) to limit the
81			number of parallel requests.
82
83			The default should be working ok for most links.
84
85			=item dns-overlap-factor = float
86
87			The DNS transport uses the minimum request latency (B<min_latency>) seen
88			during a connection as it's timing base. This factor (default: C<0.5>,
89			must be > 0) is multiplied by B<min_latency> to get the maximum sending
90			rate (= minimum send interval), i.e. a factor of C<1> means that a new
91			request might be generated every B<min_latency> seconds, which means on
92			average there should only ever be one outstanding request. A factor of
93			C<0.5> means that GVPE will send requests twice as often as the minimum
94			latency measured.
95
96			For congested or picky dns forwarders you could use a value nearer to or
97			exceeding C<1>.
98
99			The default should be working ok for most links.
100
101			=item dns-send-interval = send-interval-in-seconds
102
103			The minimum send interval (= maximum rate) that the DNS transport will
104			use to send new DNS requests. GVPE will not exceed this rate even when
105			the latency is very low. The default is C<0.01>, which means GVPE will
106			not send more than 100 DNS requests per connection per second. For
107			high-bandwidth links you could go lower, e.g. to C<0.001> or so. For
108			congested or rate-limited links, you might want to go higher, say C<0.1>,
109			C<0.2> or even higher.
110
111			The default should be working ok for most links.
112
113			=item dns-timeout-factor = float
114
115			Factor to multiply the C<min_latency> (see C<dns-overlap-factor>) by to
116			get request timeouts. The default of C<8> means that the DNS transport
117			will resend the request when no reply has been received for longer than
118			eight times the minimum (= expected) latency, assuming the request or
119			reply has been lost.
120
121			For congested links a higher value might be necessary (e.g. C<30>). If the
122			link is very stable lower values (e.g. C<2>) might work nicely. Values
123			near or below C<1> makes no sense whatsoever.
124
125			The default should be working ok for most links.
126
127	pcg	1.1	=item if-up = relative-or-absolute-path
128
129			Sets the path of a script that should be called immediately after the
130			network interface is initialized (but not neccessarily up). The following
131			environment variables are passed to it (the values are just examples):
132
133			=over 4
134
135			=item CONFBASE=/etc/gvpe
136
137			The configuration base directory.
138
139			=item IFNAME=vpn0
140
141			The interface to initialize.
142
143			=item MTU=1436
144
145			The MTU to set the interface to. You can use lower values (if done
146			consistently on all hosts), but this is usually ineffective.
147
148			=item MAC=fe:fd:80:00:00:01
149
150			The MAC address to set the interface to. The script must set the
151			interface MAC to this value. You will most likely use one of these:
152
153			ip link set $IFNAME address $MAC mtu $MTU up # GNU/Linux
154			ifconfig $IFNAME ether $MAC mtu $MTU up # FreeBSD
155
156			Please see the C<gvpe.osdep(5)> manpage for platform-specific information.
157
158			=item IFTYPE=native # or tincd
159
160			=item IFSUBTYPE=linux # or freebsd, darwin etc..
161
162			The interface type (C<native> or C<tincd>) and the subtype (usually the os
163			name in lowercase) that this gvpe was configured for. Can be used to select
164			the correct syntax to use for network-related commands.
165
166			=item NODENAME=branch1
167
168			The nickname of the current node, as passed to the gvpe daemon.
169
170			=item NODEID=1
171
172			The numerical node id of the current node. The first node mentioned in the
173			config file gets ID 1, the second ID 2 and so on.
174
175			=back
176
177			Here is a simple if-up script:
178
179			#!/bin/sh
180			ip link set $IFNAME address $MAC mtu $MTU up
181			[ $NODENAME = branch1 ] && ip addr add 10.0.0.1 dev $IFNAME
182			[ $NODENAME = branch2 ] && ip addr add 10.1.0.1 dev $IFNAME
183			ip route add 10.0.0.0/8 dev $IFNAME
184
185			More complicated examples (using routing to reduce arp traffic) can be
186			found in the etc/ subdirectory of the distribution.
187
188	pcg	1.6	=item ifname = devname
189
190			Sets the tun interface name to the given name. The default is OS-specific
191			and most probably something like C<tun0>.
192
193			=item ifpersist = yes\|true\|on \| no\|false\|off
194
195			Should the tun/tap device be made persistent, that is, should the device
196			stay up even when gvpe exits? Some versions of the tunnel device have
197			problems sending packets when gvpe is restarted in persistent mode, so
198			if the connections can be established but you cannot send packets from
199			the local node, try to set this to C<off> and do an ifconfig down on the
200			device.
201
202			=item ip-proto = numerical-ip-protocol
203
204			Sets the protocol number to be used for the rawip protocol. This is a
205			global option because all hosts must use the same protocol, and since
206			there are no port numbers, you cannot easily run more than one gvpe
207			instance using the same protocol, nor can you share the protocol with
208			other programs.
209
210			The default is 47 (GRE), which has a good chance of tunneling through
211			firewalls (but note that the rawip protocol is not GRE compatible). Other
212			common choices are 50 (IPSEC, ESP), 51 (IPSEC, AH), 4 (IPIP tunnels) or 98
213			(ENCAP, rfc1241)
214
215			=item http-proxy-host = hostname/ip
216
217			The C<http-proxy-*> family of options are only available if gvpe was
218			compiled with the C<--enable-http-proxy> option and enable tunneling of
219			tcp connections through a http proxy server.
220
221			C<http-proxy-host> and C<http-proxy-port> should specify the hostname and
222			port number of the proxy server. See C<http-proxy-loginpw> if your proxy
223			requires authentication.
224
225			Please note that gvpe will still try to resolve all hostnames in the
226			configuration file, so if you are behind a proxy without access to a dns
227			server better use numerical IP addresses.
228
229			To make best use of this option disable all protocols except tcp in your
230			config file and make sure your routers (or all other hosts) are listening
231			on a port that the proxy allows (443, https, is a common choice).
232
233			If you have a router, connecting to it will suffice. Otherwise tcp must be
234			enabled on all hosts.
235
236			Example:
237
238			http-proxy-host = proxy.example.com
239			http-proxy-port = 3128 # 8080 is another common choice
240			http-proxy-auth = schmorp:grumbeere
241
242			=item http-proxy-port = proxy-tcp-port
243
244			The port where your proxy server listens.
245
246			=item http-proxy-auth = login:password
247
248			The optional login and password used to authenticate to the proxy server,
249			seperated by a literal colon (C<:>). Only basic authentication is
250			currently supported.
251
252			=item keepalive = seconds
253
254			Sets the keepalive probe interval in seconds (default: C<60>). After this
255			many seconds of inactivity the daemon will start to send keepalive probe
256			every 5 seconds until it receives a reply from the other end. If no reply
257			is received within 30 seconds, the peer is considered unreachable and the
258			connection is closed.
259
260			=item loglevel = noise\|trace\|debug\|info\|notice\|warn\|error\|critical
261
262			Set the logging level. Connection established messages are logged at level
263			C<info>, notable errors are logged with C<error>. Default is C<info>.
264
265			=item mtu = bytes
266
267			Sets the maximum MTU that should be used on outgoing packets (basically
268			the MTU of the outgoing interface) The daemon will automatically calculate
269			maximum overhead (e.g. udp header size, encryption blocksize...) and pass
270			this information to the C<if-up> script.
271
272			Recommended values are 1500 (ethernet), 1492 (pppoe), 1472 (pptp).
273
274			This value must be the minimum of the mtu values of all hosts.
275
276			=item node = nickname
277
278			Not really a config setting but introduces a node section. The nickname is
279			used to select the right configuration section and must be passed as an
280			argument to the gvpe daemon.
281
282	pcg	1.1	=item node-up = relative-or-absolute-path
283
284			Sets a command (default: no script) that should be called whenever a
285			connection is established (even on rekeying operations). In addition
286			to the variables passed to C<if-up> scripts, the following environment
287			variables will be set:
288
289			=over 4
290
291			=item DESTNODE=branch2
292
293			The name of the remote node.
294
295			=item DESTID=2
296
297			The node id of the remote node.
298
299			=item DESTIP=188.13.66.8
300
301			The numerical IP address of the remote host (gvpe accepts connections from
302			everywhere, as long as the other host can authenticate itself).
303
304			=item DESTPORT=655 # deprecated
305
306			The UDP port used by the other side.
307
308			=item STATE=UP
309
310			Node-up scripts get called with STATE=UP, node-down scripts get called
311			with STATE=DOWN.
312
313			=back
314
315			Here is a nontrivial example that uses nsupdate to update the name => ip
316			mapping in some dns zone:
317
318			#!/bin/sh
319			{
320			echo update delete $DESTNODE.lowttl.example.net. a
321			echo update add $DESTNODE.lowttl.example.net. 1 in a $DESTIP
322			echo
323			} \| nsupdate -d -k $CONFBASE:key.example.net.
324
325			=item node-down = relative-or-absolute-path
326
327			Same as C<node-up>, but gets called whenever a connection is lost.
328
329	pcg	1.6	=item pid-file = path
330
331			The path to the pid file to check and create
332			(default: C<LOCALSTATEDIR/run/gvpe.pid>).
333
334			=item private-key = relative-path-to-key
335
336			Sets the path (relative to the config directory) to the private key
337			(default: C<hostkey>). This is a printf format string so every C<%> must
338			be doubled. A single C<%s> is replaced by the hostname, so you could
339			use paths like C<hostkeys/%s> to fetch the files at the location where
340			C<gvpectrl> puts them.
341	pcg	1.1
342	pcg	1.6	Since only the private key file of the current node is used and the
343			private key file should be kept secret per-host to avoid spoofings, it is
344			not recommended to use this feature.
345	pcg	1.1
346	pcg	1.6	=item rekey = seconds
347	pcg	1.1
348	pcg	1.6	Sets the rekeying interval in seconds (default: C<3600>). Connections are
349			reestablished every C<rekey> seconds.
350	pcg	1.1
351	pcg	1.6	=back
352	pcg	1.1
353	pcg	1.6	=head2 NODE SPECIFIC SETTINGS
354	pcg	1.1
355	pcg	1.6	The following settings are node-specific, that is, every node can have
356			different settings, even within the same gvpe instance. Settings that are
357			executed before the first node section set the defaults, settings that are
358			executed within a node section only apply to the given node.
359	pcg	1.1
360	pcg	1.6	=over 4
361	pcg	1.1
362	pcg	1.6	=item compress = yes\|true\|on \| no\|false\|off
363	pcg	1.1
364	pcg	1.6	Wether to compress data packets sent to this host (default: C<yes>).
365			Compression is really cheap even on slow computers and has no size
366			overhead at all, so enabling this is a good idea.
367	pcg	1.1
368	pcg	1.6	=item connect = ondemand \| never \| always \| disabled
369	pcg	1.1
370	pcg	1.6	Sets the connect mode (default: C<always>). It can be C<always> (always
371			try to establish and keep a connection to the given host), C<never>
372			(never initiate a connection to the given host, but accept connections),
373			C<ondemand> (try to establish a connection on the first packet sent, and
374			take it down after the keepalive interval) or C<disabled> (node is bad,
375			don't talk to it).
376	pcg	1.1
377	pcg	1.6	=item dns-domain = domain-suffix
378	pcg	1.1
379	pcg	1.7	The DNS domain suffix that points to the DNS tunnel server for this node.
380	pcg	1.1
381	pcg	1.6	The domain must point to a NS record that points to the I<dns-hostname>,
382			i.e.
383	pcg	1.1
384	pcg	1.6	dns-domainname = tunnel.example.net
385			dns-hostname = tunnel-server.example.net
386	pcg	1.1
387	pcg	1.6	Corresponds to the following DNS entries in the C<example.net> domain:
388	pcg	1.1
389	pcg	1.6	tunnel.example.net. NS tunnel-server.example.net.
390			tunnel-server.example.net. A 13.13.13.13
391	pcg	1.1
392	pcg	1.6	=item dns-hostname = hostname/ip
393	pcg	1.1
394	pcg	1.6	The address to bind the DNS tunnel socket to, similar to the C<hostname>,
395			but for the DNS tunnel protocol only. Default: C<0.0.0.0>, but that might
396			change.
397	pcg	1.1
398	pcg	1.6	=item dns-port = port-number
399	pcg	1.1
400	pcg	1.8	The port to bind the DNS tunnel socket to. Must be C<53> on DNS tunnel servers.
401	pcg	1.1
402	pcg	1.7	=item enable-dns = yes\|true\|on \| no\|false\|off
403
404	pcg	1.10	See gvpe.protocol(7) for a description of the DNS transport
405			protocol. Avoid this protocol if you can.
406
407	pcg	1.8	Enable the DNS tunneling protocol on this node, either as server or as
408	pcg	1.10	client. Support for this transport protocol is only available when gvpe
409			was compiled using the C<--enable-dns> option.
410
411			=item enable-icmp = yes\|true\|on \| no\|false\|off
412
413			See gvpe.protocol(7) for a description of the ICMP transport protocol.
414	pcg	1.8
415	pcg	1.10	Enable the ICMP transport using icmp packets of type C<icmp-type> on this
416			node.
417	pcg	1.7
418	pcg	1.1	=item enable-rawip = yes\|true\|on \| no\|false\|off
419
420	pcg	1.10	See gvpe.protocol(7) for a description of the RAW IP transport protocol.
421
422	pcg	1.1	Enable the RAW IPv4 transport using the C<ip-proto> protocol
423	pcg	1.10	(default: C<no>).
424	pcg	1.1
425	pcg	1.6	=item enable-tcp = yes\|true\|on \| no\|false\|off
426
427	pcg	1.10	See gvpe.protocol(7) for a description of the TCP transport protocol.
428
429	pcg	1.6	Enable the TCPv4 transport using the C<tcp-port> port
430	pcg	1.10	(default: C<no>). Support for this transport protocol is only available
431			when gvpe was compiled using the C<--enable-tcp> option.
432	pcg	1.6
433	pcg	1.1	=item enable-udp = yes\|true\|on \| no\|false\|off
434
435	pcg	1.10	See gvpe.protocol(7) for a description of the UDP transport protocol.
436
437	pcg	1.5	Enable the UDPv4 transport using the C<udp-port> port (default: C<no>,
438			unless no other protocol is enabled for a node, in which case this
439	pcg	1.10	protocol is enabled automatically).
440	pcg	1.5
441			NOTE: Please specify C<enable-udp = yes> if you want t use it even though
442			it might get switched on automatically, as some future version might
443			default to another default protocol.
444	pcg	1.1
445	pcg	1.11	=item icmp-type = integer
446
447			Sets the type value to be used for outgoing (and incoming) packets sent
448			via the ICMP transport.
449
450			The default is C<0> (which is C<echo-reply>, also known as
451			"ping-replies"). Other useful values include C<8> (C<echo-request>, a.k.a.
452			"ping") and C<11> (C<time-exceeded>), but any 8-bit value can be used.
453
454	pcg	1.6	=item inherit-tos = yes\|true\|on \| no\|false\|off
455
456			Wether to inherit the TOS settings of packets sent to the tunnel when
457			sending packets to this node (default: C<yes>). If set to C<yes> then
458			outgoing tunnel packets will have the same TOS setting as the packets sent
459			to the tunnel device, which is usually what you want.
460
461			=item max-retry = positive-number
462	pcg	1.1
463	pcg	1.8	The maximum interval in seconds (default: C<3600>, one hour) between
464	pcg	1.6	retries to establish a connection to this node. When a connection cannot
465			be established, gvpe uses exponential backoff capped at this value. It's
466			sometimes useful to set this to a much lower value (e.g. C<120>) on
467			connections to routers that usually are stable but sometimes are down, to
468	pcg	1.8	assure quick reconnections even after longer downtimes.
469	pcg	1.1
470	pcg	1.8	=item router-priority = 0 \| 1 \| positive-number>=2
471	pcg	1.1
472			Sets the router priority of the given host (default: C<0>, disabled). If
473			some host tries to connect to another host without a hostname, it asks
474			the router host for it's IP address. The router host is the one with the
475	pcg	1.2	highest priority larger than C<1> that is currently reachable.
476	pcg	1.1
477	pcg	1.2	Make sure all hosts always connect (C<connect = always>) to the router
478			hosts, otherwise connecting to them might be impossible.
479
480			The special value C<1> allows other hosts to route through the router
481			host, but they will never route through it by default. The value C<0>
482			disables routing. The idea behind this is that some hosts can, if
483			required, bump the C<router-priority> setting to higher than C<1> in their
484			local config to route through specific hosts. If C<router-priority> is
485			C<0>, then routing will be refused, so C<1> serves as a "enable, but do
486			not use by default" switch.
487
488	pcg	1.6	=item tcp-port = port-number
489	pcg	1.1
490	pcg	1.6	Similar to C<udp-port> (default: C<655>), but sets the TCP port number.
491	pcg	1.1
492	pcg	1.6	=item udp-port = port-number
493	pcg	1.1
494	pcg	1.6	Sets the port number used by the UDP protocol (default: C<655>, not
495			officially assigned by IANA!).
496	pcg	1.1
497			=back
498
499			=head1 CONFIG DIRECTORY LAYOUT
500
501			The default (or recommended) directory layout for the config directory is:
502
503			=over 4
504
505	pcg	1.4	=item X<gvpe.conf>
506	pcg	1.1
507			The config file.
508
509	pcg	1.4	=item X<if-up>
510	pcg	1.1
511			The if-up script
512
513	pcg	1.4	=item X<node-up>, X<node-down>
514	pcg	1.1
515			If used the node up or node-down scripts.
516
517	pcg	1.4	=item X<hostkey>
518	pcg	1.1
519			The private key (taken from C<hostkeys/nodename>) of the current host.
520
521	pcg	1.4	=item X<pubkey/nodename>
522	pcg	1.1
523			The public keys of the other nodes, one file per node.
524
525			=back
526
527			=head1 SEE ALSO
528
529			gvpe(5), gvpe(8), gvpectrl(8).
530
531			=head1 AUTHOR
532
533			Marc Lehmann <gvpe@plan9.de>
534