TINC.CONF(5) BSD File Formats Manual TINC.CONF(5)NAMEtinc.conf — tinc daemon configuration
DESCRIPTION
The files in the /usr/local/etc/tinc/ directory contain runtime and secu‐
rity information 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
configuration 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
/usr/local/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 /usr/local/etc/tinc/,
instead of /usr/local/etc/tinc/NETNAME/; the configuration file should be
/usr/local/etc/tinc/tinc.conf, and the host configuration files are now
expected to be in /usr/local/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
identification. The name has to be declared in the
/usr/local/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 host‐
names, owner surnames or location names.
PUBLIC/PRIVATE KEYS
You should use tincd -K to generate public/private keypairs. It will
generate two keys. The private key should be stored in a separate file
/usr/local/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 /usr/local/etc/tinc/NETNAME/hosts/NAME -- where
NAME stands for the name of the local tinc daemon (see NAMES).
SERVER CONFIGURATION
The server configuration of the daemon is done in the file
/usr/local/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.
The server configuration is complemented with host specific configuration
(see the next section). Although all configuration options for the local
host listed in this document can also be put in
/usr/local/etc/tinc/NETNAME/tinc.conf, it is recommended to put host spe‐
cific configuration options in the host configuration file, as this makes
it easy to exchange with other nodes.
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
system both IPv4 and IPv6 or just IPv6 listening sockets will be
created.
BindToAddress = address [port] [experimental]
If your computer has more than one IPv4 or IPv6 address, tinc
will by default listen on all of them for incoming connections.
Multiple BindToAddress variables may be specified, in which case
listening sockets for each specified address are made.
If no port is specified, the socket will be bound to the port
specified by the Port option, or to port 655 if neither is given.
To only bind to a specific port but not to a specific address,
use * for the address.
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
possible to bind only to a single interface with this variable.
This option may not work on all platforms. Also, on some plat‐
forms it will not actually bind to an interface, but rather to
the address that the interface has at the moment a socket is cre‐
ated.
Broadcast = no | mst | direct (mst) [experimental]
This option selects the way broadcast packets are sent to other
daemons. NOTE: all nodes in a VPN must use the same Broadcast
mode, otherwise routing loops can form.
no Broadcast packets are never sent to other nodes.
mst Broadcast packets are sent and forwarded via the VPN's
Minimum Spanning Tree. This ensures broadcast packets
reach all nodes.
direct Broadcast packets are sent directly to all nodes that can
be reached directly. Broadcast packets received from
other nodes are never forwarded. If the IndirectData
option is also set, broadcast packets will only be sent
to nodes which we have a meta connection to.
ConnectTo = name
Specifies which other tinc daemon to connect to on startup. Mul‐
tiple ConnectTo variables may be specified, in which case outgo‐
ing 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
connect to other daemons at all, and will instead just listen for
incoming connections.
DecrementTTL = yes | no (no) [experimental]
When enabled, tinc will decrement the Time To Live field in IPv4
packets, or the Hop Limit field in IPv6 packets, before forward‐
ing a received packet to the virtual network device or to another
node, and will drop packets that have a TTL value of zero, in
which case it will send an ICMP Time Exceeded packet back.
Do not use this option if you use switch mode and want to use
IPv6.
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 informa‐
tion about configuring the virtual network device.
DeviceType = type (platform dependent)
The type of the virtual network device. Tinc will normally auto‐
matically select the right type of tun/tap interface, and this
option should not be used. However, this option can be used to
select one of the special interface types, if support for them is
compiled in.
dummy Use a dummy interface. No packets are ever read or writ‐
ten to a virtual network device. Useful for testing, or
when setting up a node that only forwards packets for
other nodes.
raw_socket
Open a raw socket, and bind it to a pre-existing
Interface (eth0 by default). All packets are read from
this interface. Packets received for the local node are
written to the raw socket. However, at least on Linux,
the operating system does not process IP packets destined
for the local host.
multicast
Open a multicast UDP socket and bind it to the address
and port (separated by spaces) and optionally a TTL value
specified using Device. Packets are read from and writ‐
ten to this multicast socket. This can be used to con‐
nect to UML, QEMU or KVM instances listening on the same
multicast address. Do NOT connect multiple tinc daemons
to the same multicast address, this will very likely
cause routing loops. Also note that this can cause
decrypted VPN packets to be sent out on a real network if
misconfigured.
uml (not compiled in by default)
Create a UNIX socket with the filename specified by
Device, or /var/run/NETNAME.umlsocket if not specified.
tinc will wait for a User Mode Linux instance to connect
to this socket.
vde (not compiled in by default)
Uses the libvdeplug library to connect to a Virtual Dis‐
tributed Ethernet switch, using the UNIX socket specified
by Device, or /var/run/vde.ctl if not specified.
Also, in case tinc does not seem to correctly interpret packets
received from the virtual network device, it can be used to
change the way packets are interpreted:
tun (BSD and Linux)
Set type to tun. Depending on the platform, this can
either be with or without an address family header (see
below).
tunnohead (BSD)
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 pack‐
ets cannot be read from or written to the device in this
mode.
tunifhead (BSD)
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 fam‐
ily, followed by an IP header. This mode should support
both IPv4 and IPv6 packets.
tap (BSD and Linux)
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 rout‐
ing and firewall rules on them, and can also help debug‐
ging.
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 sec‐
onds 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, but whether hostnames should be
resolved while logging.
IffOneQueue = yes | no (no) [experimental]
(Linux only) Set IFF_ONE_QUEUE flag on TUN/TAP devices.
Interface = 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 of the inter‐
face. Under Windows, this variable is used to select which net‐
work interface 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.
LocalDiscovery = yes | no (no) [experimental]
When enabled, tinc will try to detect peers that are on the same
local network. This will allow direct communication using LAN
addresses, even if both peers are behind a NAT and they only Con‐
nectTo a third node outside the NAT, which normally would prevent
the peers from learning each other's LAN address.
Currently, local discovery is implemented by sending broadcast
packets to the LAN during path MTU discovery. This feature may
not work in all possible situations.
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 sup‐
ported 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 Ether‐
net are supported 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 Eth‐
ernet segments.
hub This mode is almost the same as the switch mode, but
instead every packet will be broadcast to the other dae‐
mons 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. The Name may only consist of alphanumeric and underscore
characters. If Name starts with a $, then the contents of the
environment variable that follows will be used. In that case,
invalid characters will be converted to underscores. If Name is
$HOST, but no such environment variable exist, the hostname will
be read using the gethostnname() system call.
PingInterval = seconds (60)
The number of seconds of inactivity that tinc will wait before
sending 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 tun‐
neled 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 (/usr/local/etc/tinc/NETNAME/rsa_key.priv)
The file in which the private RSA key of this tinc daemon
resides.
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.
Proxy = socks4 | socks5 | http | exec ... [experimental]
Use a proxy when making outgoing connections. The following
proxy types are currently supported:
socks4 address port [username]
Connects to the proxy using the SOCKS version 4 protocol.
Optionally, a username can be supplied which will be
passed on to the proxy server. Only IPv4 connections can
be proxied using SOCKS 4.
socks5 address port [username password]
Connect to the proxy using the SOCKS version 5 protocol.
If a username and password are given, basic user‐
name/password authentication will be used, otherwise no
authentication will be used.
http address port
Connects to the proxy and sends a HTTP CONNECT request.
exec command
Executes the given command which should set up the outgo‐
ing connection. The environment variables NAME, NODE,
REMOTEADDRES and REMOTEPORT are available.
ReplayWindow = bytes (16)
This is the size of the replay tracking window for each remote
node, in bytes. The window is a bitfield which tracks 1 packet
per bit, so for example the default setting of 16 will track up
to 128 packets in the window. In high bandwidth scenarios, set‐
ting this to a higher value can reduce packet loss from the
interaction of replay tracking with underlying real packet loss
and/or reordering. Setting this to zero will disable replay
tracking completely and pass all traffic, but leaves tinc vulner‐
able to replay-based attacks on your traffic.
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
/usr/local/etc/tinc/NETNAME/hosts/ directory. Subnets learned via
connections to other nodes and which are not present in the local
host config files are ignored.
TunnelServer = yes | no (no) [experimental]
When this option is enabled tinc will no longer forward informa‐
tion between other tinc daemons, and will only allow connections
with nodes for which host config files are present in the local
/usr/local/etc/tinc/NETNAME/hosts/ directory. Setting this
options also implicitly sets StrictSubnets.
UDPRcvBuf = bytes (OS default)
Sets the socket receive buffer size for the UDP socket, in bytes.
If unset, the default buffer size will be used by the operating
system.
UDPSndBuf = bytes (OS default)
Sets the socket send buffer size for the UDP socket, in bytes.
If unset, the default buffer size will be used by the operating
system.
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.
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 net‐
work. This will only be used when trying to make an outgoing
connection to this tinc daemon. Optionally, a port can be speci‐
fied to use for this address. Multiple Address variables can be
specified, in which case each address will be tried until a work‐
ing connection has been established.
Cipher = cipher (blowfish)
The symmetric cipher algorithm used to encrypt UDP packets. Any
cipher supported by OpenSSL is recognised. Furthermore, specify‐
ing "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 seg‐
ment size (MSS) of TCP packets to the path MTU. This helps in
situations where ICMP Fragmentation Needed or Packet too Big mes‐
sages 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, specify‐
ing "none" will turn off packet authentication.
IndirectData = yes | no (no)
When set to yes, only nodes which already have a meta connection
to you will try to establish direct communication with you. 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 authenti‐
cate 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 incom‐
ing 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 cryp‐
tographically verify it's identity and to set up a secure connec‐
tion.
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 configuration 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. 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::/64. MAC addresses are notated like
0:1a:2b:3c:4d:5e.
A Subnet can be given a weight to indicate its priority over
identical 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 pri‐
ority 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 masquerading firewall, or if UDP packet routing is dis‐
abled somehow. Setting this options also implicitly sets Indi‐
rectData.
Since version 1.0.10, tinc will automatically detect whether com‐
munication 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.
/usr/local/etc/tinc/NETNAME/tinc-up
This is the most important script. If it is present it will be
executed right after the tinc daemon has been started and has
connected to the virtual network device. It should be used to
set up the corresponding 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.
/usr/local/etc/tinc/NETNAME/tinc-down
This script is started right before the tinc daemon quits.
/usr/local/etc/tinc/NETNAME/hosts/HOST-up
This script is started when the tinc daemon with name HOST
becomes reachable.
/usr/local/etc/tinc/NETNAME/hosts/HOST-down
This script is started when the tinc daemon with name HOST
becomes unreachable.
/usr/local/etc/tinc/NETNAME/host-up
This script is started when any host becomes reachable.
/usr/local/etc/tinc/NETNAME/host-down
This script is started when any host becomes unreachable.
/usr/local/etc/tinc/NETNAME/subnet-up
This script is started when a Subnet becomes reachable. The Sub‐
net and the node it belongs to are passed in environment vari‐
ables.
/usr/local/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
subnet.
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.
Do not forget that under UNIX operating systems, you have to make the
scripts executable, using the command chmod a+x script.
FILES
The most important files are:
/usr/local/etc/tinc/
The top directory for configuration files.
/usr/local/etc/tinc/NETNAME/tinc.conf
The default name of the server configuration file for net
NETNAME.
/usr/local/etc/tinc/NETNAME/conf.d/
Optional directory from which any *.conf file will be loaded
/usr/local/etc/tinc/NETNAME/hosts/
Host configuration files are kept in this directory.
/usr/local/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
interface.
/usr/local/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.
SEE ALSOtincd(8), http://www.tinc-vpn.org/, http://www.tldp.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 com‐
mand 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 29, 2024
