Add documentation for BindToAddress.

[tinc] / doc / tinc.conf.5

.Dd 2002-04-09
.Dt TINC.CONF 5
.\" Manual page created by:
.\" Ivo Timmermans <ivo@o2w.nl>
.\" Guus Sliepen <guus@sliepen.eu.org>
.Sh NAME
.Nm tinc.conf
.Nd tinc daemon configuration
.Sh DESCRIPTION
The files in the
.Pa /etc/tinc/
directory contain runtime and security information for the tinc daemon.
.Sh NETWORKS
It is perfectly ok for you to run more than one tinc daemon.
However, in its default form,
you will soon notice that you can't use two different configuration files without the
.Fl c
option.
.Pp
We have thought of another way of dealing with this: network names.
This means that you call
.Nm
with the
.Fl n
option, which will assign a name to this daemon.
.Pp
The effect of this is that the daemon will set its configuration root to
.Pa /etc/tinc/ Ns Ar NETNAME Ns Pa / ,
where 
.Ar NETNAME
is your argument to the
.Fl n
option.
You'll notice that messages appear in syslog as coming from
.Nm tincd. Ns Ar NETNAME .
.Pp
However, it is not strictly necessary that you call tinc with the
.Fl n
option.
In this case, the network name would just be empty,
and it will be used as such.
.Nm tinc
now looks for files in
.Pa /etc/tinc/ ,
instead of 
.Pa /etc/tinc/ Ns Ar NETNAME Ns Pa / ;
the configuration file should be
.Pa /etc/tinc/tinc.conf ,
and the host configuration files are now expected to be in
.Pa /etc/tinc/hosts/ .
.Pp
But it is highly recommended that you use this feature of
.Nm tinc ,
because it will be so much clearer whom your daemon talks to.
Hence, we will assume that you use it.
.Sh NAMES
Each tinc daemon should have a name that is unique in the network which it will be part of.
The name will be used by other tinc daemons for identification.
The name has to be declared in the
.Pa /etc/tinc/ Ns Ar NETNAME Ns Pa /tinc.conf
file.
.Pp
To make things easy,
choose something that will give unique and easy to remember names to your tinc daemon(s).
You could try things like hostnames, owner surnames or location names.
.Sh PUBLIC/PRIVATE KEYS
You should use 
.Ic tincd -K
to generate public/private keypairs.
It will generate two keys.
The private key should be stored in a separate file
.Pa /etc/tinc/ Ns Ar NETNAME Ns Pa /rsa_key.priv
\-\- where 
.Ar NETNAME
stands for the network (see 
.Sx NETWORKS )
above.
The public key should be stored in the host configuration file
.Pa /etc/tinc/ Ns Ar NETNAME Ns Pa /hosts/ Ns Va NAME
\-\- where
.Va NAME
stands for the name of the local tinc daemon (see
.Sx NAMES ) .
.Sh SERVER CONFIGURATION
The server configuration of the daemon is done in the file
.Pa /etc/tinc/ Ns Ar NETNAME Ns Pa /tinc.conf .
This file consists of comments (lines started with a
.Li # )
or assignments in the form of:
.Pp
.Va Variable Li = Ar Value .
.Pp
The variable names are case insensitive, and any spaces, tabs,
newlines and carriage returns are ignored.
Note: it is not required that you put in the 
.Li =
sign, but doing so improves readability.
If you leave it out, remember to replace it with at least one space character.
.Pp
Here are all valid variables, listed in alphabetical order.
The default value is given between parentheses.
.Bl -tag -width indent
.It Va AddressFamily Li = ipv4 | ipv6 | any Po ipv4 Pc Bq experimental
This option affects the address family of listening and outgoing sockets.
If
.Qq any
is selected, then depending on the operating system both IPv4 and IPv6 or just
IPv6 listening sockets will be created.
.It Va BindToAddress Li = Ar address Bq experimental
If your computer has more than one IPv4 or IPv6 address,
.Nm tinc
will by default listen on all of them for incoming connections.
It is possible to bind only to a single address with this variable.
.Pp
This option may not work on all platforms.
.It Va BindToInterface Li = Ar interface Bq experimental
If your computer has more than one network interface,
.Nm tinc
will by default listen on all of them for incoming connections.
It is possible to bind only to a single interface with this variable.
.Pp
This option may not work on all platforms.
.It Va ConnectTo Li = Ar name
Specifies which other tinc daemon to connect to on startup.
Multiple
.Va ConnectTo
variables may be specified,
in which case outgoing connections to each specified tinc daemon are made.
The names should be known to this tinc daemon
(i.e., there should be a host configuration file for the name on the
.Va ConnectTo
line).
.Pp
If you don't specify a host with
.Va ConnectTo ,
.Nm tinc
won't try to connect to other daemons at all,
and will instead just listen for incoming connections.
.It Va Device Li = Ar device Po /dev/tap0 or /dev/net/tun Pc
The virtual network device to use.
.Nm tinc
will automatically detect what kind of device it is.
Note that you can only use one device per daemon.
The info pages of the tinc package contain more information
about configuring the virtual network device.
.It Va Hostnames Li = yes | no Pq no
This option selects whether IP addresses (both real and on the VPN) should
be resolved. Since DNS lookups are blocking, it might affect tinc's
efficiency, even stopping the daemon for a few seconds every time it does
a lookup if your DNS server is not responding.
.Pp
This does not affect resolving hostnames to IP addresses from the
host configuration files.
.It Va Interface Li = Ar interface
Defines the name of the interface corresponding to the virtual network device.
Depending on the operating system and the type of device this may or may not actually set the name.
Currently this option only affects the Linux tun/tap device.
.It Va KeyExpire Li = Ar period Pq 3600
This option controls the period the encryption keys used to encrypt the data are valid.
It is common practice to change keys at regular intervals to make it even harder for crackers,
even though it is thought to be nearly impossible to crack a single key.
.It Va MACExpire Li = Ar period Pq 600
This option controls the amount of time MAC addresses are kept before they are removed.
This only has effect when
.Va Mode
is set to
.Qq switch .
.It Va MaxTimeout Li = Ar period Pq 900
This is the maximum delay before trying to reconnect to other tinc daemons.
.It Va Mode Li = router | switch | hub Pq router
This option selects the way packets are routed to other daemons.
.Bl -tag -width indent
.It router
In this mode
.Va Subnet
variables in the host configuration files will be used to form a routing table.
Only unicast packets of routable protocols (IPv4 and IPv6) are supported in this mode.
.It switch
In this mode the MAC addresses of the packets on the VPN will be used to
dynamically create a routing table just like an Ethernet switch does.
Unicast, multicast and broadcast packets of every protocol that runs over Ethernet are supported in this mode
at the cost of frequent broadcast ARP requests and routing table updates.
.It hub
This mode is almost the same as the switch mode, but instead
every packet will be broadcast to the other daemons
while no routing table is managed.
.El
.It Va Name Li = Ar name Bq required
This is the name which identifies this tinc daemon.
It must be unique for the virtual private network this daemon will connect to.
.It Va PingTimeout Li = Ar period Pq 60
The number of seconds of inactivity that
.Nm tinc
will wait before sending a probe to the other end.
If that other end doesn't answer within that same amount of time,
the connection is terminated,
and the others will be notified of this.
.It Va PriorityInheritance Li = yes | no Po no Pc Bq experimental
When this option is enabled the value of the TOS field of tunneled IPv4 packets
will be inherited by the UDP packets that are sent out.
.It Va PrivateKey Li = Ar key Bq obsolete
The private RSA key of this tinc daemon.
It will allow this tinc daemon to authenticate itself to other daemons.
.It Va PrivateKeyFile Li = Ar filename Bq recommended
The file in which the private RSA key of this tinc daemon resides.
Note that there must be exactly one of
.Va PrivateKey
or
.Va PrivateKeyFile
specified in the configuration file.
.El
.Sh HOST CONFIGURATION FILES
The host configuration files contain all information needed
to establish a connection to those hosts.
A host configuration file is also required for the local tinc daemon,
it will use it to read in it's listen port, public key and subnets.
.Pp
The idea is that these files are portable.
You can safely mail your own host configuration file to someone else.
That other person can then copy it to his own hosts directory,
and now his tinc daemon will be able to connect to your tinc daemon.
Since host configuration files only contain public keys,
no secrets are revealed by sending out this information.
.Bl -tag -width indent
.It Va Address Li = Ar address Bq recommended
The IP address or hostname of this tinc daemon on the real network.
This wil only be used when trying to make an outgoing connection to this tinc daemon.
Multiple
.Va Address
variables can be specified, in which case each address will be tried until a working
connection has been established.
.It Va Cipher Li = Ar cipher Pq blowfish
The symmetric cipher algorithm used to encrypt UDP packets.
Any cipher supported by OpenSSL is recognised.
Furthermore, specifying
.Qq none
will turn off packet encryption.
.It Va Compression Li = Ar level Pq 0
This option sets the level of compression used for UDP packets.
Possible values are 0 (off), 1 (fast) and any integer up to 9 (best).
.It Va Digest Li = Ar digest Pq sha1
The digest algorithm used to authenticate UDP packets.
Any digest supported by OpenSSL is recognised.
Furthermore, specifying
.Qq none
will turn off packet authentication.
.It Va IndirectData Li = yes | no Pq no
This option specifies whether other tinc daemons besides the one you specified with
.Va ConnectTo
can make a direct connection to you.
This is especially useful if you are behind a firewall
and it is impossible to make a connection from the outside to your tinc daemon.
Otherwise, it is best to leave this option out or set it to no.
.It Va MACLength Li = Ar length Pq 4
The length of the message authentication code used to authenticate UDP packets.
Can be anything from
.Qq 0
up to the length of the digest produced by the digest algorithm.
.It Va Port Li = Ar port Pq 655
The port number on which this tinc daemon is listening for incoming connections.
.It Va PublicKey Li = Ar key Bq obsolete
The public RSA key of this tinc daemon.
It will be used to cryptographically verify it's identity and to set up a secure connection.
.It Va PublicKeyFile Li = Ar filename Bq obsolete
The file in which the public RSA key of this tinc daemon resides.
.Pp
From version 1.0pre4 on
.Nm tinc
will store the public key directly into the host configuration file in PEM format,
the above two options then are not necessary.
Either the PEM format is used, or exactly one of the above two options must be specified
in each host configuration file,
if you want to be able to establish a connection with that host.
.It Va Subnet Li = Ar address Ns Op Li / Ns Ar prefixlength
The subnet which this tinc daemon will serve.
.Nm tinc
tries to look up which other daemon it should send a packet to by searching the appropriate subnet.
If the packet matches a subnet,
it will be sent to the daemon who has this subnet in his host configuration file.
Multiple
.Va Subnet
variables can be specified.
.Pp
Subnets can either be single MAC, IPv4 or IPv6 addresses,
in which case a subnet consisting of only that single address is assumed,
or they can be a IPv4 or IPv6 network address with a prefixlength.
Shorthand notations are not supported.
For example, IPv4 subnets must be in a form like 192.168.1.0/24,
where 192.168.1.0 is the network address and 24 is the number of bits set in the netmask.
Note that subnets like 192.168.1.1/24 are invalid!
Read a networking HOWTO/FAQ/guide if you don't understand this.
IPv6 subnets are notated like fec0:0:0:1:0:0:0:0/64.
MAC addresses are notated like 0:1a:2b:3c:4d:5e.
.It Va TCPOnly Li = yes | no Pq no
If this variable is set to yes,
then the packets are tunnelled over the TCP connection instead of a UDP connection.
This is especially useful for those who want to run a tinc daemon
from behind a masquerading firewall,
or if UDP packet routing is disabled somehow.
Setting this options also implicitly sets IndirectData.
.El
.Sh FILES
.Bl -tag -width indent
.It Pa /etc/tinc/
The top directory for configuration files.
.It Pa /etc/tinc/ Ns Ar NETNAME Ns Pa /tinc.conf
The default name of the server configuration file for net
.Ar NETNAME .
.It Pa /etc/tinc/ Ns Ar NETNAME Ns Pa /hosts/
Host configuration files are kept in this directory.
.It Pa /etc/tinc/ Ns Ar NETNAME Ns Pa /tinc-up
If an executable file with this name exists,
it will be executed right after the tinc daemon has connected to the virtual network device.
It can be used to set up the corresponding network interface.
.Pp
The environment variable
.Ev $NETNAME
will be passed to the executable.
If specified with the
.Va Interface
configuration variable,
or if the virtual network device is a Linux tun/tap device,
the environment variable
.Ev $INTERFACE
will be set to the name of the network interface.
.It Pa /etc/tinc/ Ns Ar NETNAME Ns Pa /tinc-down
If an executable file with this name exists,
it will be executed right before the tinc daemon is going to close
its connection to the virtual network device.
The same environment variables will be passed as mentioned above.
.El
.Sh SEE ALSO
.Xr tincd 8 ,
.Pa http://tinc.nl.linux.org/ ,
.Pa http://www.linuxdoc.org/LDP/nag2/ .
.Pp
The full documentation for
.Nm tinc
is maintained as a Texinfo manual.
If the info and tinc programs are properly installed at your site, the command
.Ic info tinc
should give you access to the complete manual.
.Pp
.Nm tinc
comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it under certain conditions;
see the file COPYING for details.