[root@host boot]# openvpn --config /etc/openvpn/server.conf  --mktun
Thu Jan 24 09:42:40 2008 Note: Cannot open TUN/TAP dev /dev/net/tun: No such file or directory (errno=2)
Thu Jan 24 09:42:40 2008 Note: Attempting fallback to kernel 2.2 TUN/TAP interface
Thu Jan 24 09:42:40 2008 Cannot allocate TUN/TAP dev dynamically
Thu Jan 24 09:42:40 2008 Exiting

пробуем по другому:
[root@host boot]# openvpn --config /etc/openvpn/server.conf
Thu Jan 24 09:44:25 2008 OpenVPN 2.0.9 i686-pc-linux [SSL] [LZO] [EPOLL] built on Jan 24 2008
Thu Jan 24 09:44:25 2008 Diffie-Hellman initialized with 1024 bit key
Thu Jan 24 09:44:25 2008 TLS-Auth MTU parms [ L:1542 D:138 EF:38 EB:0 ET:0 EL:0 ]
Thu Jan 24 09:44:25 2008 Note: Cannot open TUN/TAP dev /dev/net/tun: No such file or directory (errno=2)
Thu Jan 24 09:44:25 2008 Note: Attempting fallback to kernel 2.2 TUN/TAP interface
Thu Jan 24 09:44:25 2008 Cannot allocate TUN/TAP dev dynamically
Thu Jan 24 09:44:25 2008 Exiting

[root@host boot]# ls -al /dev/net/tun
ls: /dev/net/tun: No such file or directory

[root@host modules]# modprobe tun
FATAL: Could not load /lib/modules/2.6.9-023stab044.4-enterprise/modules.dep: No such file or directory
[root@host modules]# uname -a
Linux host 2.6.9-023stab044.4-enterprise #1 SMP Thu May 24 17:41:23 MSD 2007 i686 athlon i386 GNU/Linux
[root@host modules]#

[root@host modules]# ls -al /lib/modules/
total 9
drwxr-xr-x   6 root root 1024 Jan 24 09:45 .
drwxr-xr-x  12 root root 4096 Jan 24 09:19 ..
drwxr-xr-x   3 root root 1024 Jan 24 06:38 2.6.9-67.0.1.EL
drwxr-xr-x   2 root root 1024 Jan 24 09:08 2.6.9-67.0.1.ELhugemem
drwxr-xr-x   2 root root 1024 Jan 24 09:07 2.6.9-67.0.1.ELsmp
drwxr-xr-x   2 root root 1024 Dec 19 15:58 kabi-4.0-0

обычно у меня все гладко..
что зделать что бы этот tun появился :)