Linode Forum

[stephenr317]

I am trying to set up an OpenVPN server on Ubuntu 10.10 64 bit and am using the community guide as reference. I have gone through the guide several times but I am still having an issue. When I attempt to start opevpn I get the following error:

Code: root@boromir:/etc/openvpn# openvpn server.conf
Fri Mar 25 07:47:22 2011 OpenVPN 2.1.0 x86_64-pc-linux-gnu [SSL] [LZO2] [EPOLL] [PKCS11] [MH] [PF_INET6] [eurephia] built on Jul 12 2010
Fri Mar 25 07:47:22 2011 NOTE: OpenVPN 2.1 requires '--script-security 2' or higher to call user-defined scripts or executables
Fri Mar 25 07:47:22 2011 Diffie-Hellman initialized with 2048 bit key
Fri Mar 25 07:47:22 2011 /usr/bin/openssl-vulnkey -q -b 2048 -m <modulus omitted>
Fri Mar 25 07:47:23 2011 TLS-Auth MTU parms [ L:1542 D:138 EF:38 EB:0 ET:0 EL:0 ]
Fri Mar 25 07:47:23 2011 ROUTE default_gateway=74.207.232.1
Fri Mar 25 07:47:23 2011 Note: Cannot open TUN/TAP dev /dev/net/tun: No such device (errno=19)
Fri Mar 25 07:47:23 2011 Note: Attempting fallback to kernel 2.2 TUN/TAP interface
Fri Mar 25 07:47:23 2011 Cannot allocate TUN/TAP dev dynamically
Fri Mar 25 07:47:23 2011 Exiting

To confirm the module cannot be found:

Code: root@boromir:/etc/openvpn# modprobe tun
FATAL: Module tun not found.


How to I install this module or set it up correctly? I have tried a few things I've found googling but nothing has worked thus far.

Thanks!

[Guspaz]

You installed udev?

[Stever]

Code:  ~ # uname -r
2.6.38-x86_64-linode17
 ~ # zgrep CONFIG_TUN /proc/config.gz
# CONFIG_TUN is not set


I thought the linode kernels had the TUN device built-in, but it appears not to be - do the 32-bit kernels include TUN?

You can:

1) Run your distro kernel with pv-grub

2) Download the linode kernel source and build the module yourself

3) Ask linode to include the TUN driver in their kernel

[Stever]

Code:  # pwd
/tmp/2.6.35.7-linode29
 # grep CONFIG_TUN .config
CONFIG_TUN=y


Yep - the 32-bit kernels have the TUN device built-in, while the 64-bit don't. I'd probably file a support ticket on this one, I doubt linode meant it to be this way.

[stephenr317]

Thanks for the help! I thought that was the case but wasn't 100% sure. I'll open a support ticket for tun to be included in 64 bit kernel.