Most users will only require one ``tun'' device (tun0). If you have used more (i.e., a number other than `1' in the pseudo-device line in the kernel configuration file) then alter all references to ``tun0'' below to reflect whichever device number you are using.
The easiest way to make sure that the tun0 device is configured correctly is to re-make it. To do this, execute the following commands:
# cd /dev
# ./MAKEDEV tun0
If you require 16 tunnel devices in your kernel, you will need to create more than just tun0:
# cd /dev
# ./MAKEDEV tun15
Also, to confirm that the kernel is configured correctly, the following command should give the indicated output:
$ ifconfig tun0
tun0: flags=8050<POINTOPOINT,RUNNING,MULTICAST> mtu 1500
$
The RUNNING flag may not yet be set, in which case you'll see:
$ ifconfig tun0
tun0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
$