VTun - Setup

Setup

General recommendations

IP tunnel

    type tun;
    proto udp;
    keepalive yes; 
    up {
       ifconfig "%% xxxxxxx";
    };

This will give you reliable and the fastest possible Point-to-Point tunnel. Use this tunnel type whenever it's possible, especially if performance and efficiency is concerned. If you need compression, use LZO or TCP protocol and ZLIB. Currently TUN device is supported on Linux and FreeBSD, Solaris driver will be available soon.

Ethernet tunnel

    type ether;
    proto udp;
    keepalive yes; 
    up {
       ifconfig "%% xxxxxxx";
    };

This will give you reliable and fast Ethernet tunnel. You can tunnel any protocol that works with Ethernet IP, IPX, Appletalk, DECnet, etc If you need compression, use LZO or TCP protocol and ZLIB.

PPP or SLIP tunnel

    type tty;
    proto tcp;
    keepalive yes; 
    up {
       ppp "xxxxxxxxxxx";
    };

This will give you reliable and fast PPP or SLIP tunnel. You can safely use compression.

Anything else :))

    type pipe; or type tty; if it depends on TTYs
    proto tcp;
    keepalive yes;
    up {
       program /xx/xx "yyyyy";
    }

Never use UDP with 'pipe' tunnel type. VTun allows it, but it is not a good idea. Compression, encryption and shaping are safe for almost everything.

Config samples

Example 1
We have to create virtual tunnels between 3 private IP networks in different locations on the Internet. All networks are being serviced by Linux boxes having dedicated links and a fixed IP address to the Internet.
Network addresses and servers:
  192.168.0.0 - Server S1
  192.168.1.0 - Server S2
  192.168.2.0 - Server S3
We can setup S1 as a VTun server for S2 and S3 and create 3 tunnels. But in this case we'll get a star net topology with unreliable and inefficient routing. That's why we will create 6 tunnels, each server will have two tunnels with other servers.
S1 will have only server config, S2 will have server and client config and S3 only client config.

Here are VTun configs for each server:

Server S1
default {
  type tun;
  proto udp;
  comp lzo:1;
  keepalive yes;
}

# Tunnel between S1 and S2 (192.168.0.0 <-> 192.168.1.0)
# Server entry
s2 {
  pass XXXX;
  ifconfig "%% 192.168.0.1 pointopoint 192.168.0.2";
  route "add -net 192.168.1.0 gw 192.168.0.2";
  program /sbin/arp "-sD 192.168.0.2 eth0 pub";
}

# Tunnel between S1 and S3 (192.168.0.0 <-> 192.168.2.0)
# Server entry
s3_1 {
  pass XXXX;
  ifconfig "%% 192.168.0.1 pointopoint 192.168.0.3";
  route "add -net 192.168.2.0 gw 192.168.0.3";
  program /sbin/arp "-sD 192.168.0.3 eth0 pub";
}
Start vtund as 'vtund -s'

Server S2
default {
  type tun;
  proto udp;
  comp lzo:1;
  keepalive yes;
}

# Tunnel between S2 and S1 (192.168.1.0 <-> 192.168.0.0)
# Client entry
s2 {
  pass XXXX;
  ifconfig "%% 192.168.0.2 pointopoint 192.168.0.1";
  route "add -net 192.168.0.0 gw 192.168.0.1";
}

# Tunnel between S2 and S3 (192.168.1.0 <-> 192.168.2.0)
# Server entry
s3_2 {
  pass XXXX;
  ifconfig "%% 192.168.0.2 pointopoint 192.168.0.3";
  route "add -net 192.168.2.0 gw 192.168.0.3";
}
	
Start vtund as 
'vtund -s'
'vtund s2 real_address_of_s1'

Server S3
# Tunnel between S3 and S1 (192.168.2.0 <-> 192.168.0.0)
# Client entry
s3_1 {
  pass XXXX;
  ifconfig "%% 192.168.0.3 pointopoint 192.168.0.1";
  route "add -net 192.168.0.0 gw 192.168.0.1";
}

# Tunnel between S3 and S2 (192.168.2.0 <-> 192.168.1.0)
# Client entry
s3_2 {
  pass XXXX;
  ifconfig "%% 192.168.0.3 pointopoint 192.168.0.2";
  route "add -net 192.168.1.0 gw 192.168.0.2";
}
   
Start vtund as
'vtund s3_1 real_address_of_s1'
'vtund s3_2 real_address_of_s2'

Note: This example uses RedHat Linux commands syntax, check your manuals for correct syntax on your system.

Example 2
We will add more examples soon.