TINC.CONF(5) BSD File Formats Manual TINC.CONF(5)
NAME
tinc.conf — tinc daemon configuration
DESCRIPTION
The files in the /etc/tinc/ directory contain runtime and security informa‐
tion for the tinc daemon.
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 con‐
figuration files without the -c option.
We have thought of another way of dealing with this: network names. This
means that you call tinc.conf with the -n option, which will assign a name
to this daemon.
The effect of this is that the daemon will set its configuration root to
/etc/tinc/NETNAME/, where NETNAME is your argument to the -n option. You'll
notice that messages appear in syslog as coming from tincd.NETNAME.
However, it is not strictly necessary that you call tinc with the -n option.
In this case, the network name would just be empty, and it will be used as
such. tinc now looks for files in /etc/tinc/, instead of
/etc/tinc/NETNAME/; the configuration file should be /etc/tinc/tinc.conf,
and the host configuration files are now expected to be in /etc/tinc/hosts/.
But it is highly recommended that you use this feature of tinc, because it
will be so much clearer whom your daemon talks to. Hence, we will assume
that you use it.
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 identifi‐
cation. The name has to be declared in the /etc/tinc/NETNAME/tinc.conf
file.
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.
You should use tincd -K to generate public/private keypairs. It will gener‐
ate two keys. The private key should be stored in a separate file
/etc/tinc/NETNAME/rsa_key.priv -- where NETNAME stands for the network (see
NETWORKS) above. The public key should be stored in the host configuration
file /etc/tinc/NETNAME/hosts/NAME -- where NAME stands for the name of the
local tinc daemon (see NAMES).
The server configuration of the daemon is done in the file
/etc/tinc/NETNAME/tinc.conf. This file consists of comments (lines started
with a #) or assignments in the form of:
Variable = Value.
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
= sign, but doing so improves readability. If you leave it out, remember to
replace it with at least one space character.
Here are all valid variables, listed in alphabetical order. The default
value is given between parentheses.
AddressFamily = ipv4 | ipv6 | any (any)
This option affects the address family of listening and outgoing
sockets. If "any" is selected, then depending on the operating sys‐
tem both IPv4 and IPv6 or just IPv6 listening sockets will be cre‐
ated.
BindToAddress = address [experimental]
If your computer has more than one IPv4 or IPv6 address, 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.
This option may not work on all platforms.
BindToInterface = interface [experimental]
If your computer has more than one network interface, tinc will by
default listen on all of them for incoming connections. It is pos‐
sible to bind only to a single interface with this variable.
This option may not work on all platforms.
ConnectTo = name
Specifies which other tinc daemon to connect to on startup. Multi‐
ple 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 ConnectTo line).
If you don't specify a host with ConnectTo, tinc won't try to con‐
nect to other daemons at all, and will instead just listen for
incoming connections.
Device = device (/dev/tap0, /dev/net/tun or other depending on platform)
The virtual network device to use. tinc will automatically detect
what kind of device it is. Note that you can only use one device
per daemon. Under Windows, use Interface instead of Device. The
info pages of the tinc package contain more information about con‐
figuring the virtual network device.
DeviceType = tun | tunnohead | tunifhead | tap (only supported on BSD
platforms)
The type of the virtual network device. Tinc will normally automat‐
ically select the right type, and this option should not be used.
However, in case tinc does not seem to correctly interpret packets
received from the virtual network device, using this option might
help.
tun Set type to tun. Depending on the platform, this can either
be with or without an address family header (see below).
tunnohead
Set type to tun without an address family header. Tinc will
expect packets read from the virtual network device to start
with an IP header. On some platforms IPv6 packets cannot be
read from or written to the device in this mode.
tunifhead
Set type to tun with an address family header. Tinc will
expect packets read from the virtual network device to start
with a four byte header containing the address family, fol‐
lowed by an IP header. This mode should support both IPv4
and IPv6 packets.
tap Set type to tap. Tinc will expect packets read from the
virtual network device to start with an Ethernet header.
DirectOnly = yes | no (no) [experimental]
When this option is enabled, packets that cannot be sent directly to
the destination node, but which would have to be forwarded by an
intermediate node, are dropped instead. When combined with the
IndirectData option, packets for nodes for which we do not have a
meta connection with are also dropped.
Forwarding = off | internal | kernel (internal) [experimental]
This option selects the way indirect packets are forwarded.
off Incoming packets that are not meant for the local node, but
which should be forwarded to another node, are dropped.
internal
Incoming packets that are meant for another node are for‐
warded by tinc internally.
This is the default mode, and unless you really know you
need another forwarding mode, don't change it.
kernel Incoming packets are always sent to the TUN/TAP device, even
if the packets are not for the local node. This is less
efficient, but allows the kernel to apply its routing and
firewall rules on them, and can also help debugging.
GraphDumpFile = filename [experimental]
If this option is present, tinc will dump the current network graph
to the file filename every minute, unless there were no changes to
the graph. The file is in a format that can be read by graphviz
tools. If filename starts with a pipe symbol |, then the rest of
the filename is interpreted as a shell command that is executed, the
graph is then sent to stdin.
Hostnames = yes | no (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.
This does not affect resolving hostnames to IP addresses from the
host configuration files.
Interface = interface
Defines the name of the interface corresponding to the virtual net‐
work device. Depending on the operating system and the type of
device this may or may not actually set the name of the interface.
Under Windows, this variable is used to select which network inter‐
face will be used. If you specified a Device, this variable is
almost always already correctly set.
KeyExpire = seconds (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.
MACExpire = seconds (600)
This option controls the amount of time MAC addresses are kept
before they are removed. This only has effect when Mode is set to
"switch".
MaxTimeout = seconds (900)
This is the maximum delay before trying to reconnect to other tinc
daemons.
Mode = router | switch | hub (router)
This option selects the way packets are routed to other daemons.
router In this mode 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.
This is the default mode, and unless you really know you
need another mode, don't change 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 sup‐
ported in this mode at the cost of frequent broadcast ARP
requests and routing table updates.
This mode is primarily useful if you want to bridge Ethernet
segments.
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.
Name = name [required]
This is the name which identifies this tinc daemon. It must be
unique for the virtual private network this daemon will connect to.
PingInterval = seconds (60)
The number of seconds of inactivity that tinc will wait before send‐
ing a probe to the other end.
PingTimeout = seconds (5)
The number of seconds to wait for a response to pings or to allow
meta connections to block. If the other end doesn't respond within
this time, the connection is terminated, and the others will be
notified of this.
PriorityInheritance = yes | no (no) [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.
PrivateKey = key [obsolete]
The private RSA key of this tinc daemon. It will allow this tinc
daemon to authenticate itself to other daemons.
PrivateKeyFile = filename (/etc/tinc/NETNAME/rsa_key.priv)
The file in which the private RSA key of this tinc daemon resides.
Note that there must be exactly one of PrivateKey or PrivateKeyFile
specified in the configuration file.
ProcessPriority = low | normal | high
When this option is used the priority of the tincd process will be
adjusted. Increasing the priority may help to reduce latency and
packet loss on the VPN.
StrictSubnets = yes | no (no) [experimental]
When this option is enabled tinc will only use Subnet statements
which are present in the host config files in the local
/etc/tinc/NETNAME/hosts/ directory.
TunnelServer = yes | no (no) [experimental]
When this option is enabled tinc will no longer forward information
between other tinc daemons, and will only allow connections with
nodes for which host config files are present in the local
/etc/tinc/NETNAME/hosts/ directory. Setting this options also
implicitly sets StrictSubnets.
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.
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.
Address = address [port] [recommended]
The IP address or hostname of this tinc daemon on the real network.
This will only be used when trying to make an outgoing connection to
this tinc daemon. Optionally, a port can be specified to use for
this address. Multiple Address variables can be specified, in which
case each address will be tried until a working connection has been
established.
Cipher = cipher (blowfish)
The symmetric cipher algorithm used to encrypt UDP packets. Any
cipher supported by OpenSSL is recognised. Furthermore, specifying
"none" will turn off packet encryption. It is best to use only
those ciphers which support CBC mode.
ClampMSS = yes | no (yes)
This option specifies whether tinc should clamp the maximum segment
size (MSS) of TCP packets to the path MTU. This helps in situations
where ICMP Fragmentation Needed or Packet too Big messages are
dropped by firewalls.
Compression = level (0)
This option sets the level of compression used for UDP packets.
Possible values are 0 (off), 1 (fast zlib) and any integer up to 9
(best zlib), 10 (fast lzo) and 11 (best lzo).
Digest = digest (sha1)
The digest algorithm used to authenticate UDP packets. Any digest
supported by OpenSSL is recognised. Furthermore, specifying "none"
will turn off packet authentication.
IndirectData = yes | no (no)
This option specifies whether other tinc daemons besides the one you
specified with ConnectTo can make a direct connection to you. This
is especially useful if you are behind a firewall and it is impossi‐
ble to make a connection from the outside to your tinc daemon. Oth‐
erwise, it is best to leave this option out or set it to no.
MACLength = length (4)
The length of the message authentication code used to authenticate
UDP packets. Can be anything from "0" up to the length of the
digest produced by the digest algorithm.
PMTU = mtu (1514)
This option controls the initial path MTU to this node.
PMTUDiscovery = yes | no (yes)
When this option is enabled, tinc will try to discover the path MTU
to this node. After the path MTU has been discovered, it will be
enforced on the VPN.
Port = port (655)
The port number on which this tinc daemon is listening for incoming
connections, which is used if no port number is specified in an
Address statement.
PublicKey = key [obsolete]
The public RSA key of this tinc daemon. It will be used to crypto‐
graphically verify it's identity and to set up a secure connection.
PublicKeyFile = filename [obsolete]
The file in which the public RSA key of this tinc daemon resides.
From version 1.0pre4 on 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 configu‐
ration file, if you want to be able to establish a connection with
that host.
Subnet = address[/prefixlength[#weight]]
The subnet which this tinc daemon will serve. 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 Subnet variables can be specified.
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 net‐
work 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.
A Subnet can be given a weight to indicate its priority over identi‐
cal Subnets owned by different nodes. The default weight is 10.
Lower values indicate higher priority. Packets will be sent to the
node with the highest priority, unless that node is not reachable,
in which case the node with the next highest priority will be tried,
and so on.
TCPOnly = yes | no (no [obsolete])
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 mas‐
querading firewall, or if UDP packet routing is disabled somehow.
Setting this options also implicitly sets IndirectData.
Since version 1.0.10, tinc will automatically detect whether commu‐
nication via UDP is possible or not.
SCRIPTS
Apart from reading the server and host configuration files, tinc can also
run scripts at certain moments. Under Windows (not Cygwin), the scripts
should have the extension .bat.
/etc/tinc/NETNAME/tinc-up
This is the most important script. If it is present it will be exe‐
cuted right after the tinc daemon has been started and has connected
to the virtual network device. It should be used to set up the cor‐
responding network interface, but can also be used to start other
things. Under Windows you can use the Network Connections control
panel instead of creating this script.
/etc/tinc/NETNAME/tinc-down
This script is started right before the tinc daemon quits.
/etc/tinc/NETNAME/hosts/HOST-up
This script is started when the tinc daemon with name HOST becomes
reachable.
/etc/tinc/NETNAME/hosts/HOST-down
This script is started when the tinc daemon with name HOST becomes
unreachable.
/etc/tinc/NETNAME/host-up
This script is started when any host becomes reachable.
/etc/tinc/NETNAME/host-down
This script is started when any host becomes unreachable.
/etc/tinc/NETNAME/subnet-up
This script is started when a Subnet becomes reachable. The Subnet
and the node it belongs to are passed in environment variables.
/etc/tinc/NETNAME/subnet-down
This script is started when a Subnet becomes unreachable.
The scripts are started without command line arguments, but can make use of
certain environment variables. Under UNIX like operating systems the names
of environment variables must be preceded by a $ in scripts. Under Windows,
in .bat files, they have to be put between % signs.
NETNAME
If a netname was specified, this environment variable contains it.
NAME Contains the name of this tinc daemon.
DEVICE Contains the name of the virtual network device that tinc uses.
INTERFACE
Contains the name of the virtual network interface that tinc uses.
This should be used for commands like ifconfig.
NODE When a host becomes (un)reachable, this is set to its name. If a
subnet becomes (un)reachable, this is set to the owner of that sub‐
net.
REMOTEADDRESS
When a host becomes (un)reachable, this is set to its real address.
REMOTEPORT
When a host becomes (un)reachable, this is set to the port number it
uses for communication with other tinc daemons.
SUBNET When a subnet becomes (un)reachable, this is set to the subnet.
WEIGHT When a subnet becomes (un)reachable, this is set to the subnet
weight.
FILES
The most important files are:
/etc/tinc/
The top directory for configuration files.
/etc/tinc/NETNAME/tinc.conf
The default name of the server configuration file for net NETNAME.
/etc/tinc/NETNAME/hosts/
Host configuration files are kept in this directory.
/etc/tinc/NETNAME/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 inter‐
face.
/etc/tinc/NETNAME/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.
tincd(8), http://www.tinc-vpn.org/, http://www.linuxdoc.org/LDP/nag2/.
The full documentation for tinc is maintained as a Texinfo manual. If the
info and tinc programs are properly installed at your site, the command info
tinc should give you access to the complete manual.
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.
April 11, 2010