Ubuntu Manpage: vtund.conf - VTun(Virtual Tunnel) daemon configuration file.

Provided by: vtun_3.0.4-2ubuntu0.22.04.1_amd64

NAME

       vtund.conf - VTun(Virtual Tunnel) daemon configuration file.

DESCRIPTION

       Configuration file for vtund(8) virtual tunnel daemon.

       File consists of sections in the form:

              name {
                keyword value;
                keyword value;
                ..
              }

       Semicolon  at  the  end  of each keyword-value pair is required, as well as grouping curly
       braces {}.  Lines which begin with '#' characters are comments.

       Name of section (name) can be one of:

       options
              this section specifies general options for vtund

       default
              specifies default options for all sessions

       session
              (any other  word  except  "options"  and  "default")  introduces  new  session  and
              specifies options for it.

       All keyword names can be abbreviated to a minimum of 4 characters.

GENERAL OPTIONS

       This  section,  named  options,  specifies  general  options to use by vtund(8).  Possible
       keywords are:

       type stand|inetd
              server type. vtund(8) can operate in standalone mode (stand), that is  the  default
              (but not available on no-MMU systems), or be invoked from inetd(8).

       ipv4   use  IPv4  as  transport medium. This is the default. Inside the tunnel other types
              are of course usable.

       ipv6   use IPv6 as transport medium.

       port portnumber
              server port number to listen on or connect to.   By  default,  vtund(8)  uses  port
              5000.

       bindaddr list
              server listen address. Used to force vtund to bind to the specific address and port
              in server mode.  Format:
                bindaddr {
                 option value;
                };

              bindaddr options:

              iface if_name
                     use interface address if_name as the bind address.

              addr addr
                     bind address.  Can be either IP address or host name.

       timeout seconds
              General timeout.

       persist yes|keep|no
              persist mode.  If yes, the client  will  try  to  reconnect  to  the  server  after
              connection  termination.   If keep, the client will not remove and re-add the tunXX
              or tapXX device when reconnecting.  If no, the client will  exit  (default).   This
              option is ignored by the server.

       syslog number|name
              syslog facility specification, either numeric or name (from syslog (3)).

       ppp path
              path to pppd(8) program.  Can be used in session sections.

       ifconfig path
              path to ifconfig(8) program.  Can be used in session sections.

       route path
              path to route(8) program.  Can be used in session sections.

       ip path
              path to iproute(8) program.  Can be used in session sections.

       firewall path
              program for the firewall setup.

       All  the  ppp,  ifconfig,  route  and  firewall  parameters  can  specify  a  filename for
       corresponding program or equivalent (or  shell  script).   This  parameters  are  used  in
       session sections to setup network interfaces.

SESSION OPTIONS

Session options can be specified inside session section or inside default section.
Default parameters apply to any session section but can be overwritten there. Parameters
are:

passwd secret
password for authentication. This should be the same in client and server.

type type
type of tunnel. Possible tunnel types are:

tun IP tunnel (no PPP, Ether etc headers)

ether Ethernet tunnel

tty serial tunnel (PPP, SLIP etc)

pipe pipe tunnel

Default tunnel type is tty. This option is ignored by client.

device dev
network device to use. You can choose tapXX for ether tunnel or tunXX for tun
tunnel. By default vtund(8) will automatically select available device.

proto tcp|udp
protocol to use. By default, vtund(8) will use TCP protocol. UDP is recommended
for ether and tun tunnels only. This option is ignored by the client.

nat_hack client|server|no
side to use nat_hack on. By default, vtund(8) uses a 'no' setting. The side that
the NAT hack is enabled on will perform a delayed UDP socket connect. Should only
be enabled for the side outside of the NAT (typically the server)! Setting 'client'
on the server or 'server' on the client is ignored, as to make a single
configuration file reusable on both sides.

This is only relevant if you use proto udp. The NAT hack delays the UDP socket
connect until the first UDP packet is received from the other side of the tunnel.
The socket is then connected to the actual source port of the packet (on the NAT
box) and not to the one indicated in the handshake (which is behind NAT and
probably unreachable). The first echo request is also disabled on the side with
the NAT hack enabled.

Currently the mechanism works only for one side, for a single NAT traversal. If
you enable it for both sides, both will wait for a first packet and the tunnel will
never transport any data.

Security warning! Due to the nature of the delayed connection, the tunnel can be
hijacked in theory by an attacker behind the same NAT, sending the first UDP packet
to the server UDP port, before the real client does. If you do not understand the
risks, or want to remain as secure as possible behind this kind of NAT router, use
proto tcp as a NAT traversal solution.

Because of the security issue mentioned above, this option might be disabled during
compilation (configure --disable-nathack).

timeout secounds
Connect timeout.

compress method[:level]
specifies compression method to use. Compression methods include:

no no compression

yes default compression method

zlib ZLIB compression

lzo LZO compression (if compiled in)

You can also specify level of compression using one digit (1 is best speed, 9 is
best compression ratio). This option is ignored by the client.

encrypt method[:level]
specifies encryption method to use. Encryption methods include:

no no encryption

yes default encryption method (blowfish128ecb)

blowfish128ecb
Blowfish cipher, 128 bit key, mode ECB

blowfish128cbc
Blowfish cipher, 128 bit key, mode CBC

blowfish128cfb
Blowfish cipher, 128 bit key, mode CFB

blowfish128ofb
Blowfish cipher, 128 bit key, mode OFB

blowfish256ecb
Blowfish cipher, 256 bit key, mode ECB

blowfish256cbc
Blowfish cipher, 256 bit key, mode CBC

blowfish256cfb
Blowfish cipher, 256 bit key, mode CFB

blowfish256ofb
Blowfish cipher, 256 bit key, mode OFB

aes128ecb

oldblowfish128ecb
Blowfish cipher, 128bit key, mode ECB
(for use with 2.6 clients only) AES cipher, 128 bit key, mode ECB

aes128cbc
AES cipher, 128 bit key, mode CBC

aes128cfb
AES cipher, 128 bit key, mode CFB

aes128ofb
AES cipher, 128 bit key, mode OFB

aes256ecb
AES cipher, 256 bit key, mode ECB

aes256cbc
AES cipher, 256 bit key, mode CBC

aes256cfb
AES cipher, 256 bit key, mode CFB

aes256ofb
AES cipher, 256 bit key, mode OFB

This option is ignored by the client.

keepalive yes|no|interval:count
enable or disable connection keep-alive. Time interval is a period between
connection checks, in seconds, and count is the maximum number of retries (yes =
30:4). This option is ignored by the server.

stat yes|no
enable or disable statistics. If enabled vtund(8) will log statistic counters to
/var/log/vtund/session_X every 5 minutes.

speed kbps
specifies speed of the connection in kilobits/second. Valid values for kbps are
8,16,32,64,128,256,etc. 0 (the default) means maximum possible speed without
shaping. You can specify speed in form in:out, where in is speed to client, out -
from the client. Single number means the same speed for in and out. This option
ignored by the client.

srcaddr list
local (source) address. Used to force vtund to bind to the specific address and
port. Format:
srcaddr {
option value;
option value;
..
};

srcaddr options:

iface if_name
use interface address if_name as the source address.

addr addr
source address. Can be either IP address or host name.

port portnumber
source port.

multi value
control multiple connections. value can be yes or allow to allow multiple
connections, no or deny to deny them or killold to allow new connection and kill
old one. Ignored by the client.

up list
list of programs to run after connection has been established. Used to initialize
protocols, devices, routing and firewall. This option looks like whole section
inside of session section. For now, it's impossible to run up commands on no-MMU
systems, so the section is ignored there. Format:
up {
option value;
option value;
..
};

Options inside up (and down) blocks:

program path arguments [wait]
run specified program. path is the full path to the program, arguments is
all arguments to pass to it (enclosed in double quotes). If wait specified,
vtund will wait program termination. Special characters that can be used
inside arguments parameter:

´ (single quotes) - group arguments
\ (back slash) - escape character
%d - TUN or TAP device or TTY port name
%% (double percent) - same as %d
%A - Local IP address
%P - Local TCP or UDP port
%a - Remote IP address
%p - Remote TCP or UDP port
%h - Host profile name

ppp arguments
run program specified by ppp statement in options section. All special
character described above are valid in arguments here.

ifconfig arguments
run program specified by ifconfig statement in options section.

route arguments
run program specified by route statement in options section.

ip arguments
run program specified by ip statement in options section.

firewall arguments
run program specified by firewall statement in options section.

down list
list of programs to run after connection has been terminated. It is similar to up
parameter above. Not available on no-MMU systems too. Format:
down {
option value;
option value;
..
};

NOTES

       Options ignored by the client are supplied by the server at the run time or are used  only
       on the server side.

AUTHOR