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=head1 NAME |
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|
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gvpe.conf - configuration file for the GNU VPE daemon |
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|
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=head1 SYNOPSIS |
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|
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udp-port = 407 |
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mtu = 1492 |
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ifname = vpn0 |
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|
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node = branch1 |
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hostname = 1.2.3.4 |
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|
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node = branch2 |
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hostname = www.example.net |
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udp-port = 500 # this host uses a different udp-port |
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|
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node = branch3 |
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connect = ondemand |
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|
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=head1 DESCRIPTION |
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|
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The gvpe config file consists of a series of lines that contain C<variable |
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= value> pairs. Empty lines are ignored. Comments start with a C<#> and |
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extend to the end of the line. They can be used on their own lines, or |
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after any directives. Spaces are allowed before or after the C<=> sign or |
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after values, but not within the variable names or values themselves. |
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|
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The only exception to the above is the "on" directive that can prefix any |
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C<name = value> setting and will only "execute" it on the named node, or |
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(if the nodename starts with "!") on all nodes except the named one. |
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|
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name = value |
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on branch1 loglevel = noise |
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on !branch2 connect = ondemand |
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|
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All settings are executed "in order", that is, later settings of the same |
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variable overwrite earlier ones. |
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|
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=head1 ANATOMY OF A CONFIG FILE |
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|
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Usually, a config file starts with global settings (like the udp port to |
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listen on), followed by node-specific sections that begin with a C<node = |
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nickname> line. |
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|
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Every node that is part of the network must have a section that starts |
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with C<node = nickname>. The number and order of the nodes is important |
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and must be the same on all hosts. It is not uncommon for node sections to |
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be completely empty - if the default values are right. |
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|
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Node-specific settings can be used at any time. If used before the first |
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node section they will set the default values for all following nodes. |
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|
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=head1 CONFIG VARIABLES |
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|
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=head2 GLOBAL SETTINGS |
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|
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Global settings will affect the behaviour of the running gvpe daemon, that |
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is, they are in some sense node-specific (config files can set different |
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values on different nodes using C<on>), but will affect the behaviour of |
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the gvpe daemon and all connections it creates. |
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|
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=over 4 |
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|
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=item loglevel = noise|trace|debug|info|notice|warn|error|critical |
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|
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Set the logging level. Connection established messages are logged at level |
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C<info>, notable errors are logged with C<error>. Default is C<info>. |
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|
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=item node = nickname |
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|
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Not really a config setting but introduces a node section. The nickname is |
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used to select the right configuration section and must be passed as an |
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argument to the gvpe daemon. |
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|
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=item private-key = relative-path-to-key |
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|
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Sets the path (relative to the config directory) to the private key |
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(default: C<hostkey>). This is a printf format string so every C<%> must |
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be doubled. A single C<%s> is replaced by the hostname, so you could |
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use paths like C<hostkeys/%s> to fetch the files at the location where |
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C<gvpectrl> puts them. |
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|
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Since only the private key file of the current node is used and the |
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private key file should be kept secret per-host to avoid spoofings, it is |
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not recommended to use this feature. |
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|
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=item ifpersist = yes|true|on | no|false|off |
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|
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Should the tun/tap device be made persistent, that is, should the device |
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stay up even when gvpe exits? Some versions of the tunnel device have |
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problems sending packets when gvpe is restarted in persistent mode, so |
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if the connections can be established but you cannot send packets from |
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the local node, try to set this to C<off> and do an ifconfig down on the |
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device. |
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|
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=item ifname = devname |
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|
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Sets the tun interface name to the given name. The default is OS-specific |
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and most probably something like C<tun0>. |
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|
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=item rekey = seconds |
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|
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Sets the rekeying interval in seconds (default: C<3600>). Connections are |
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reestablished every C<rekey> seconds. |
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|
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=item keepalive = seconds |
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|
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Sets the keepalive probe interval in seconds (default: C<60>). After this |
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many seconds of inactivity the daemon will start to send keepalive probe |
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every 5 seconds until it receives a reply from the other end. If no reply |
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is received within 30 seconds, the peer is considered unreachable and the |
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connection is closed. |
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|
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=item mtu = bytes |
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|
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Sets the maximum MTU that should be used on outgoing packets (basically |
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the MTU of the outgoing interface) The daemon will automatically calculate |
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maximum overhead (e.g. udp header size, encryption blocksize...) and pass |
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this information to the C<if-up> script. |
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|
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Recommended values are 1500 (ethernet), 1492 (pppoe), 1472 (pptp). |
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|
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This value must be the minimum of the mtu values of all hosts. |
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|
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=item ip-proto = numerical-ip-protocol |
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|
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Sets the protocol number to be used for the rawip protocol. This is a |
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global option because all hosts must use the same protocol, and since |
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there are no port numbers, you cannot easily run more than one gvpe |
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instance using the same protocol, nor can you share the protocol with |
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other programs. |
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|
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The default is 47 (GRE), which has a good chance of tunneling through |
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firewalls (but note that the rawip protocol is not GRE compatible). Other |
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common choices are 50 (IPSEC, ESP), 51 (IPSEC, AH), 4 (IPIP tunnels) or 98 |
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(ENCAP, rfc1241) |
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|
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=item if-up = relative-or-absolute-path |
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|
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Sets the path of a script that should be called immediately after the |
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network interface is initialized (but not neccessarily up). The following |
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environment variables are passed to it (the values are just examples): |
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|
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=over 4 |
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|
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=item CONFBASE=/etc/gvpe |
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|
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The configuration base directory. |
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|
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=item IFNAME=vpn0 |
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|
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The interface to initialize. |
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|
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=item MTU=1436 |
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|
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The MTU to set the interface to. You can use lower values (if done |
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consistently on all hosts), but this is usually ineffective. |
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|
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=item MAC=fe:fd:80:00:00:01 |
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|
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The MAC address to set the interface to. The script *must* set the |
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interface MAC to this value. You will most likely use one of these: |
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|
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ip link set $IFNAME address $MAC mtu $MTU up # GNU/Linux |
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ifconfig $IFNAME ether $MAC mtu $MTU up # FreeBSD |
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|
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Please see the C<gvpe.osdep(5)> manpage for platform-specific information. |
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|
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=item IFTYPE=native # or tincd |
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|
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=item IFSUBTYPE=linux # or freebsd, darwin etc.. |
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|
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The interface type (C<native> or C<tincd>) and the subtype (usually the os |
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name in lowercase) that this gvpe was configured for. Can be used to select |
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the correct syntax to use for network-related commands. |
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|
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=item NODENAME=branch1 |
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|
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The nickname of the current node, as passed to the gvpe daemon. |
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|
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=item NODEID=1 |
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|
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The numerical node id of the current node. The first node mentioned in the |
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config file gets ID 1, the second ID 2 and so on. |
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|
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=back |
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|
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Here is a simple if-up script: |
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|
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#!/bin/sh |
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ip link set $IFNAME address $MAC mtu $MTU up |
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[ $NODENAME = branch1 ] && ip addr add 10.0.0.1 dev $IFNAME |
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[ $NODENAME = branch2 ] && ip addr add 10.1.0.1 dev $IFNAME |
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ip route add 10.0.0.0/8 dev $IFNAME |
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|
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More complicated examples (using routing to reduce arp traffic) can be |
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found in the etc/ subdirectory of the distribution. |
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|
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=item node-up = relative-or-absolute-path |
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|
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Sets a command (default: no script) that should be called whenever a |
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connection is established (even on rekeying operations). In addition |
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to the variables passed to C<if-up> scripts, the following environment |
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variables will be set: |
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|
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=over 4 |
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|
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=item DESTNODE=branch2 |
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The name of the remote node. |
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|
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=item DESTID=2 |
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|
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The node id of the remote node. |
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|
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=item DESTIP=188.13.66.8 |
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|
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The numerical IP address of the remote host (gvpe accepts connections from |
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everywhere, as long as the other host can authenticate itself). |
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|
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=item DESTPORT=655 # deprecated |
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|
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The UDP port used by the other side. |
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|
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=item STATE=UP |
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|
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Node-up scripts get called with STATE=UP, node-down scripts get called |
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with STATE=DOWN. |
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|
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=back |
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|
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Here is a nontrivial example that uses nsupdate to update the name => ip |
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mapping in some dns zone: |
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|
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#!/bin/sh |
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{ |
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echo update delete $DESTNODE.lowttl.example.net. a |
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echo update add $DESTNODE.lowttl.example.net. 1 in a $DESTIP |
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echo |
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} | nsupdate -d -k $CONFBASE:key.example.net. |
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|
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=item node-down = relative-or-absolute-path |
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|
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Same as C<node-up>, but gets called whenever a connection is lost. |
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|
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=item http-proxy-host = hostname/ip |
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|
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The C<http-proxy-*> family of options are only available if gvpe was |
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compiled with the C<--enable-http-proxy> option and enable tunneling of |
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tcp connections through a http proxy server. |
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|
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C<http-proxy-host> and C<http-proxy-port> should specify the hostname and |
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port number of the proxy server. See C<http-proxy-loginpw> if your proxy |
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requires authentication. |
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|
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Please note that gvpe will still try to resolve all hostnames in the |
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configuration file, so if you are behind a proxy without access to a dns |
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server better use numerical IP addresses. |
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|
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To make best use of this option disable all protocols except tcp in your |
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config file and make sure your routers (or all other hosts) are listening |
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on a port that the proxy allows (443, https, is a common choice). |
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|
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If you have a router, connecting to it will suffice. Otherwise tcp must be |
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enabled on all hosts. |
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|
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Example: |
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|
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http-proxy-host = proxy.example.com |
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http-proxy-port = 3128 # 8080 is another common choice |
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http-proxy-auth = schmorp:grumbeere |
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|
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=item http-proxy-port = proxy-tcp-port |
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|
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The port where your proxy server listens. |
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|
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=item http-proxy-auth = login:password |
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|
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The optional login and password used to authenticate to the proxy server, |
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seperated by a literal colon (C<:>). Only basic authentication is |
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currently supported. |
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|
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=item pid-file = path |
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|
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The path to the pid file to check and create (Default: |
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|
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=back |
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|
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=head2 NODE SPECIFIC SETTINGS |
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|
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The following settings are node-specific, that is, every node can have |
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different settings, even within the same gvpe instance. Settings that are |
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executed before the first node section set the defaults, settings that are |
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executed within a node section only apply to the given node. |
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|
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=over 4 |
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|
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=item udp-port = port-number |
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|
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Sets the port number used by the UDP protocol (default: C<655>, not |
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officially assigned by IANA!). |
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|
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=item tcp-port = port-number |
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|
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Similar to C<udp-port> (default: C<655>), but sets the TCP port number. |
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|
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=item enable-rawip = yes|true|on | no|false|off |
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|
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Enable the RAW IPv4 transport using the C<ip-proto> protocol |
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(default: C<no>). This is the best choice, since the overhead per packet |
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is only 38 bytes, as opposed to UDP's 58 (or TCP's 60+). |
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|
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=item enable-udp = yes|true|on | no|false|off |
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|
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Enable the UDPv4 transport using the C<udp-port> port (default: C<no>, |
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unless no other protocol is enabled for a node, in which case this |
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protocol is enabled automatically). This is a good general choice since |
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UDP tunnels well through many firewalls. |
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|
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NOTE: Please specify C<enable-udp = yes> if you want t use it even though |
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it might get switched on automatically, as some future version might |
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default to another default protocol. |
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|
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=item enable-tcp = yes|true|on | no|false|off |
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|
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Enable the TCPv4 transport using the C<tcp-port> port |
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(default: C<no>). Support for this horribly unsuitable protocol is only |
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available when gvpe was compiled using the C<--enable-tcp> option. Never |
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use this transport unless you really must, it is horribly ineffiecent and |
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resource-intensive compared to the other transports. |
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|
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=item router-priority = 0 | 1 | positive-number>2 |
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|
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Sets the router priority of the given host (default: C<0>, disabled). If |
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some host tries to connect to another host without a hostname, it asks |
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the router host for it's IP address. The router host is the one with the |
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highest priority larger than C<1> that is currently reachable. |
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|
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Make sure all hosts always connect (C<connect = always>) to the router |
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hosts, otherwise connecting to them might be impossible. |
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|
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The special value C<1> allows other hosts to route through the router |
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host, but they will never route through it by default. The value C<0> |
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disables routing. The idea behind this is that some hosts can, if |
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required, bump the C<router-priority> setting to higher than C<1> in their |
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local config to route through specific hosts. If C<router-priority> is |
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C<0>, then routing will be refused, so C<1> serves as a "enable, but do |
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not use by default" switch. |
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|
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=item connect = ondemand | never | always | disabled |
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|
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Sets the connect mode (default: C<always>). It can be C<always> (always |
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try to establish and keep a connection to the given host), C<never> |
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(never initiate a connection to the given host, but accept connections), |
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C<ondemand> (try to establish a connection on the first packet sent, and |
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take it down after the keepalive interval) or C<disabled> (node is bad, |
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don't talk to it). |
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|
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=item inherit-tos = yes|true|on | no|false|off |
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|
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Wether to inherit the TOS settings of packets sent to the tunnel when |
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sending packets to this node (default: C<yes>). If set to C<yes> then |
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outgoing tunnel packets will have the same TOS setting as the packets sent |
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to the tunnel device, which is usually what you want. |
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|
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=item compress = yes|true|on | no|false|off |
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|
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Wether to compress data packets sent to this host (default: C<yes>). |
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Compression is really cheap even on slow computers and has no size |
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overhead at all, so enabling this is a good idea. |
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|
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=item max-retry = positive-number |
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|
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The maximum interval in seconds (default: C<28800>, 8 hours) between |
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retries to establish a connection to this node. When a connection cannot |
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be established, gvpe uses exponential backoff capped at this value. It's |
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sometimes useful to set this to a much lower value (e.g. C<120>) on |
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connections to routers that usually are stable but sometimes are down, to |
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assure quick reconnections. |
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|
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=back |
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|
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=head1 CONFIG DIRECTORY LAYOUT |
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|
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The default (or recommended) directory layout for the config directory is: |
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|
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=over 4 |
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|
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=item X<gvpe.conf> |
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|
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The config file. |
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|
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=item X<if-up> |
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|
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The if-up script |
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|
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=item X<node-up>, X<node-down> |
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|
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If used the node up or node-down scripts. |
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|
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=item X<hostkey> |
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|
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The private key (taken from C<hostkeys/nodename>) of the current host. |
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|
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=item X<pubkey/nodename> |
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|
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The public keys of the other nodes, one file per node. |
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|
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=back |
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|
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=head1 SEE ALSO |
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|
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gvpe(5), gvpe(8), gvpectrl(8). |
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|
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=head1 AUTHOR |
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|
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Marc Lehmann <gvpe@plan9.de> |
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|
