anytun(8)
=========

NAME
----
anytun - anycast tunneling daemon

SYNOPSIS
--------

*anytun*
[ *-h|--help* ]
[ *-D|--nodaemonize* ]
[ *-u|--username* <username> ]
[ *-g|--groupname* <groupname> ]
[ *-C|--chroot* <path> ]
[ *-P|--write-pid* <filename> ]
[ *-L|--log* <target>:<level>[,<param1>[,<param2>[..]]] ]
[ *-i|--interface* <ip-address> ]
[ *-p|--port* <port> ]
[ *-r|--remote-host* <hostname|ip> ]
[ *-o|--remote-port* <port> ]
[ *-4|--ipv4-only* ]
[ *-6|--ipv6-only* ]
[ *-I|--sync-interface* <ip-address> ]
[ *-S|--sync-port* port> ]
[ *-M|--sync-hosts* <hostname|ip>[:<port>][,<hostname|ip>[:<port>][...]] ]
[ *-X|--control-host* <hostname|ip>[:<port>]
[ *-d|--dev* <name> ]
[ *-t|--type* <tun|tap> ]
[ *-n|--ifconfig* <local>/<prefix> ]
[ *-x|--post-up-script* <script> ]
[ *-R|--route* <net>/<prefix length> ]
[ *-m|--mux* <mux-id> ]
[ *-s|--sender-id* <sender id> ]
[ *-w|--window-size* <window size> ]
[ *-k|--kd-prf* <kd-prf type> ]
[ *-e|--role <role>* ]
[ *-E|--passphrase* <pass phrase> ]
[ *-K|--key* <master key> ]
[ *-A|--salt* <master salt> ]
[ *-c|--cipher* <cipher type> ]
[ *-a|--auth-algo* <algo type> ]
[ *-b|--auth-tag-length* <length> ]

DESCRIPTION
-----------

*Anytun* is an implementation of the Secure Anycast Tunneling Protocol
(SATP). It provides a complete VPN solution similar to OpenVPN or
IPsec in tunnel mode. The main difference is that anycast enables the
setup of tunnels between an arbitrary combination of anycast, unicast
and multicast hosts.

OPTIONS
-------

*Anytun* has been designed as a peer to peer application, so there is
no difference between client and server. The following options can be
passed to the daemon:

-D|--nodaemonize
~~~~~~~~~~~~~~~~

This option instructs *anytun* to run in foreground
instead of becoming a daemon which is the default.

-u|--username <username>
~~~~~~~~~~~~~~~~~~~~~~~~

run as this user. If no group is specified (*-g*) the default group of 
the user is used. The default is to not drop privileges.

-g|--groupname <groupname>
~~~~~~~~~~~~~~~~~~~~~~~~~~

run as this group. If no username is specified (*-u*) this gets ignored.
The default is to not drop privileges.

-C|--chroot <path>
~~~~~~~~~~~~~~~~~~

Instruct *anytun* to run in a chroot jail. The default is 
to not run in chroot.

-P|--write-pid <filename>
~~~~~~~~~~~~~~~~~~~~~~~~~

Instruct *anytun* to write it's pid to this file. The default is 
to not create a pid file.

-L|--log <target>:<level>[,<param1>[,<param2>[..]]]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

add log target to logging system. This can be invoked several times
in order to log to different targets at the same time. Every target 
hast its own log level which is a number between 0 and 5. Where 0 means
disabling log and 5 means debug messages are enabled.

The following targets are supported:

* *syslog* - log to syslog daemon, parameters <level>[,<logname>[,<facility>]]
* *file* - log to file, parameters <level>[,<path>]
* *stdout* - log to standard output, parameters <level>
* *stderr* - log to standard error, parameters <level> 

The file target can be used more the once with different levels.
If no target is provided at the command line a single target with the 
following config is added:

*syslog:3,uanytun,daemon*

-i|--interface <ip address>
~~~~~~~~~~~~~~~~~~~~~~~~~~~

This IP address is used as the sender address for outgoing
packets. In case of anycast tunnel endpoints, the anycast
IP has to be used. In case of unicast endpoints, the
address is usually derived correctly from the routing
table. The default is to not use a special inteface and just
bind on all interfaces.

-p|--port <port>
~~~~~~~~~~~~~~~~

local anycast(data) port to bind to

The local UDP port that is used to send and receive the
payload data. The two tunnel endpoints can use different
ports. If a tunnel endpoint consists of multiple anycast
hosts, all hosts have to use the same port. default: 4444

-r|--remote-host <hostname|ip>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

remote host

This option can be used to specify the remote tunnel
endpoint. In case of anycast tunnel endpoints, the
anycast IP address has to be used. If you do not specify
an address, it is automatically determined after receiving
the first data packet.

-o|--remote-port <port>
~~~~~~~~~~~~~~~~~~~~~~~
remote port

The UDP port used for payload data by the remote host
(specified with -p on the remote host). If you do not specify
a port, it is automatically determined after receiving
the first data packet.

-4|--ipv4-only
~~~~~~~~~~~~~~

Resolv to IPv4 addresses only. The default is to resolv both
IPv4 and IPv6 addresses.

-6|--ipv6-only
~~~~~~~~~~~~~~

Resolv to IPv6 addresses only. The default is to resolv both
IPv4 and IPv6 addresses.

-I|--sync-interface <ip-address>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

local unicast(sync) ip address to bind to

This option is only needed for tunnel endpoints consisting
of multiple anycast hosts. The unicast IP address of
the anycast host can be used here. This is needed for
communication with the other anycast hosts. The default is to 
not use a special inteface and just bind on all interfaces. However
this is only the case if synchronisation is active see *--sync-port*.

-S|--sync-port <port>
~~~~~~~~~~~~~~~~~~~~~

local unicast(sync) port to bind to

This option is only needed for tunnel endpoints
consisting of multiple anycast hosts. This port is used
by anycast hosts to synchronize information about tunnel
endpoints. No payload data is transmitted via this port.
By default the synchronisation is disabled an therefore the
port is kept empty.

It is possible to obtain a list of active connections
by telnetting into this port. This port is read-only
and unprotected by default. It is advised to protect
this port using firewall rules and, eventually, IPsec.

-M|--sync-hosts <hostname|ip>[:<port>],[<hostname|ip>[:<port>][...]]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

remote hosts to sync with

This option is only needed for tunnel endpoints consisting
of multiple anycast hosts. Here, one has to specify all
unicast IP addresses of all other anycast hosts that
comprise the anycast tunnel endpoint. By default synchronisation is
disabled and therefore this is empty. Mind that the port can be
omitted in which case port 2323 is used. If you want to specify an
ipv6 address and a port you have to use [ and ] to seperate the address
from the port, eg.: [::1]:1234. If you want to use the default port 
[ and ] can be omitted.

-X|--control-host <hostname|ip>[:<port>]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

fetch the config from this host. The default is not to use a control
host and therefore this is empty. Mind that the port can be omitted 
in which case port 2323 is used. If you want to specify an
ipv6 address and a port you have to use [ and ] to seperate the address
from the port, eg.: [::1]:1234. If you want to use the default port 
[ and ] can be omitted.

-d|--dev <name>
~~~~~~~~~~~~~~~
device name

By default, tapN is used for Ethernet tunnel interfaces,
and tunN for IP tunnels, respectively. This option can
be used to manually override these defaults.

-t|--type <tun|tap>
~~~~~~~~~~~~~~~~~~~

device type

Type of the tunnels to create. Use tap for Ethernet
tunnels, tun for IP tunnels.

-n|--ifconfig <local>/<prefix>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

*<local>* the local IP address for the tun/tap device

*<prefix>* the prefix length of the network

The local IP address and prefix length. The remote tunnel endpoint
has to use a different IP address in the same subnet

-x|--post-up-script <script>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This option instructs *anytun* to run this script after the interface 
is created. By default no script will be executed.

-R|--route <net>/<prefix length>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

add a route to connection. This can be invoked several times.

-m|--mux <mux-id>
~~~~~~~~~~~~~~~~~

the multiplex id to use. default: 0

-s|--sender-id  <sender id>
~~~~~~~~~~~~~~~~~~~~~~~~~~~

Each anycast tunnel endpoint needs a uniqe sender id
(1, 2, 3, ...). It is needed to distinguish the senders
in case of replay attacks. This option can be ignored on
unicast endpoints. default: 0

-w|--window-size <window size>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

seqence window size

Sometimes, packets arrive out of order on the receiver
side. This option defines the size of a list of received
packets' sequence numbers. If, according to this list,
a received packet has been previously received or has
been transmitted in the past, and is therefore not in
the list anymore, this is interpreted as a replay attack
and the packet is dropped. A value of 0 deactivates this
list and, as a consequence, the replay protection employed
by filtering packets according to their secuence number.
By default the sequence window is disabled and therefore a
window size of 0 is used.

-k|--kd--prf <kd-prf type>
~~~~~~~~~~~~~~~~~~~~~~~~~~

key derivation pseudo random function.

The pseudo random function which is used for calculating the 
session keys and session salt.

Possible values:

* *null* - no random function, keys and salt are set to 0..00
* *aes-ctr* - AES in counter mode with 128 Bits, default value
* *aes-ctr-128* - AES in counter mode with 128 Bits
* *aes-ctr-192* - AES in counter mode with 192 Bits
* *aes-ctr-256* - AES in counter mode with 256 Bits

-e|--role <role>
~~~~~~~~~~~~~~~~

SATP uses different session keys for inbound and outbound traffic. The
role parameter is used to determine which keys to use for outbound or
inbound packets. On both sides of a vpn connection different roles have 
to be used. Possible values are *left* and *right*. You may also use 
*alice* or *server* as a replacement for *left* and *bob* or *client* as 
a replacement for *right*. By default *left* is used.

-E|--passphrase <pass phrase>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This passphrase is used to generate the master key and master salt.
For the master key the last n bits of the SHA256 digest of the 
passphrase (where n is the length of the master key in bits) is used. 
The master salt gets generated with the SHA1 digest. 
You may force a specific key and or salt by using *--key* and *--salt*.

-K|--key <master key>
~~~~~~~~~~~~~~~~~~~~~

master key to use for key derivation

Master key in hexadecimal notation, eg
01a2b3c4d5e6f708a9b0cadbecfd0fa1, with a mandatory length
of 32, 48 or 64 characters (128, 192 or 256 bits).

-A|--salt <master salt>
~~~~~~~~~~~~~~~~~~~~~~~

master salt to use for key derivation

Master salt in hexadecimal notation, eg
01a2b3c4d5e6f708a9b0cadbecfd, with a mandatory length
of 28 characters (14 bytes).

-c|--cipher <cipher type>
~~~~~~~~~~~~~~~~~~~~~~~~~

payload encryption algorithm

Encryption algorithm used for encrypting the payload

Possible values:

* *null* - no encryption
* *aes-ctr* - AES in counter mode with 128 Bits, default value
* *aes-ctr-128* - AES in counter mode with 128 Bits
* *aes-ctr-192* - AES in counter mode with 192 Bits
* *aes-ctr-256* - AES in counter mode with 256 Bits

-a|--auth-algo <algo type>
~~~~~~~~~~~~~~~~~~~~~~~~~~

message authentication algorithm

This option sets the message authentication algorithm.

Possible values:

* *null* - no message authentication
* *sha1* - HMAC-SHA1, default value

If HMAC-SHA1 is used, the packet length is increased. The additional bytes 
contain the authentication data. see *-b|--auth-tag-length* for more info.

-b|--auth-tag-length <length>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The number of bytes to use for the auth tag. This value defaults to 10 bytes 
unless the *null* auth algo is used in which case it defaults to 0. 


EXAMPLES
--------

P2P Setup between two unicast enpoints:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Host A:
^^^^^^^

anytun -r hostb.example.com -t tun -n 192.168.123.1/30 -c aes-ctr-256 -k aes-ctr-256 \
       -E have_a_very_safe_and_productive_day -e left

Host B:
^^^^^^^
anytun -r hosta.example.com -t tun -n 192.168.123.2/30 -c aes-ctr-256 -k aes-ctr-256 \
       -E have_a_very_safe_and_productive_day -e right


One unicast and one anycast tunnel endpoint:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
Unicast tunnel endpoint:
^^^^^^^^^^^^^^^^^^^^^^^^

anytun -r anycast.anytun.org -d anytun0 -t tun -n 192.0.2.2/30 -a null -c null -w 0 -e client

Anycast tunnel endpoints:
^^^^^^^^^^^^^^^^^^^^^^^^^

On the host with unicast hostname unicast1.anycast.anytun.org and anycast 
hostname anycast.anytun.org:
-------------------------------------------------------------------------------------------------
# anytun -i anycast.anytun.org -d anytun0 -t tun -n 192.0.2.1/30 -a null -c null -w 0 -e server \
         -S 2342 -M unicast2.anycast.anytun.org:2342,unicast3.anycast.anytun.org:2342
-------------------------------------------------------------------------------------------------

On the host with unicast hostname unicast2.anycast.anytun.org and anycast
hostname anycast.anytun.org:
-------------------------------------------------------------------------------------------------
# anytun -i anycast.anytun.org -d anytun0 -t tun -n 192.0.2.1/30 -a null -c null -w 0 -e server \
         -S 2342 -M unicast1.anycast.anytun.org:2342,unicast3.anycast.anytun.org:2342
-------------------------------------------------------------------------------------------------

On the host with unicast hostname unicast3.anycast.anytun.org and anycast
hostname anycast.anytun.org:
-------------------------------------------------------------------------------------------------
# anytun -i anycast.anytun.org -d anytun0 -t tun -n 192.0.2.1/30 -a null -c null -w 0 -e server \
         -S 2342 -M unicast1.anycast.anytun.org:2342,unicast2.anycast.anytun.org:2342
-------------------------------------------------------------------------------------------------

For more sophisticated examples (like multiple unicast endpoints to one
anycast tunnel endpoint) please consult the man page of anytun-config(8).


BUGS
----
Most likely there are some bugs in *anytun*. If you find a bug, please let
the developers know at satp@anytun.org. Of course, patches are preferred.

SEE ALSO
--------
anytun-config(8), anytun-controld(8), anytun-showtables(8)

AUTHORS
-------
Design of SATP and wizards of this implementation:

Othmar Gsenger <otti@anytun.org>
Erwin Nindl <nine@anytun.org>
Christian Pointner <equinox@anytun.org>

Debian packaging:

Andreas Hirczy <ahi@itp.tu-graz.ac.at>

Manual page:

Alexander List <alex@debian.org>

RESOURCES
---------

Main web site: http://www.anytun.org/


COPYING
-------

Copyright \(C) 2007-2008 Othmar Gsenger, Erwin Nindl and Christian
Pointner. This  program  is  free software;  you  can redistribute
it and/or modify it under the terms of the GNU General Public License
version 2 as published by the Free Software Foundation.