OpenVpn TUN/TAP

unminser · 05-08-2010, 01:17 PM

i installed the openvpn and now try to run it but:

Code:

[root@server openvpn]# /usr/sbin/openvpn  server.conf
Sat May  8 13:15:51 2010 OpenVPN 2.1.1 x86_64-redhat-linux [SSL] [LZO2] [EPOLL] [PKCS11] built on May  8 2010
Sat May  8 13:15:51 2010 NOTE: OpenVPN 2.1 requires '--script-security 2' or higher to call user-defined scripts or executables
Sat May  8 13:15:51 2010 Diffie-Hellman initialized with 1024 bit key
Sat May  8 13:15:51 2010 TLS-Auth MTU parms [ L:1542 D:138 EF:38 EB:0 ET:0 EL:0 ]
Sat May  8 13:15:51 2010 ROUTE default_gateway=191.255.255.1
Sat May  8 13:15:51 2010 Note: Cannot open TUN/TAP dev /dev/net/tun: Permission denied (errno=13)
Sat May  8 13:15:51 2010 Note: Attempting fallback to kernel 2.2 TUN/TAP interface
Sat May  8 13:15:51 2010 Cannot allocate TUN/TAP dev dynamically
Sat May  8 13:15:51 2010 Exiting

catkin · 05-09-2010, 06:14 AM

What is the output of

Code:

ls -l /dev/net/tun
lsmod | grep tun

unminser · 05-09-2010, 09:20 AM

Code:

[root@server /]# ls -l /dev/net/tun
crw------- 1 root root 10, 200 May  7 21:51 /dev/net/tun
[root@dok /]# lsmod | grep tun
bash: lsmod: command not found
[root@server /]#

catkin · 05-09-2010, 09:51 AM

Quote:

Originally Posted by unminser

Code:

[root@server /]# ls -l /dev/net/tun
crw------- 1 root root 10, 200 May  7 21:51 /dev/net/tun
[root@dok /]# lsmod | grep tun
bash: lsmod: command not found
[root@server /]#

Strange; no lsmod command? Maybe RedHat has another way to list modules loaded into the kernel. Maybe try /sbin/lsmod. I'm guessing the underlying problem is tun is not in the kernel.

unminser · 05-09-2010, 10:19 AM

Code:

[root@server /]# find -name lsmod
./sbin/lsmod
[root@server /]# ./sbin/lsmod | grep tun
[root@server /]#
[root@server /]# find -name tun
./dev/net/tun
[root@server /]#

im using centos 5.?.?

catkin · 05-09-2010, 10:41 AM

Quote:

Originally Posted by unminser

Code:

[root@server /]# find -name lsmod
./sbin/lsmod
[root@server /]# ./sbin/lsmod | grep tun
[root@server /]#
[root@server /]# find -name tun
./dev/net/tun
[root@server /]#

im using centos 5.?.?

Seems you have an unusual $PATH for root -- it usually includes /sbin. For interest echo $PATH

The was no output from ./sbin/lsmod | grep tun showing the tun module was not loaded. Presuming tun is not built in to the kernel that might be enough to explain the symptoms. IDK how to load modules in RedHat but this page looks helpful. Looks like you just need to run /sbin/modprobe tun and, if it works OK (confirm with lsmod), try OpenVPN again.

unminser · 05-09-2010, 10:58 AM

Code:

[root@server /]# echo $PATH
/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/home/rabbit/bin
[root@server  /]# ./sbin/lsmod | grep tun
[root@server  /]# /sbin/modprobe tun
FATAL: Could not load /lib/modules/2.6.18-028stab067.4/modules.dep: No such file or directory
[root@server  /]# ./sbin/modprobe tun
FATAL: Could not load /lib/modules/2.6.18-028stab067.4/modules.dep: No such file or directory
[root@server  /]#

catkin · 05-09-2010, 11:11 AM

Quote:

Originally Posted by unminser

Code:

[root@server /]# echo $PATH
/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/home/rabbit/bin
[root@server  /]# ./sbin/lsmod | grep tun
[root@server  /]# /sbin/modprobe tun
FATAL: Could not load /lib/modules/2.6.18-028stab067.4/modules.dep: No such file or directory
[root@server  /]# ./sbin/modprobe tun
FATAL: Could not load /lib/modules/2.6.18-028stab067.4/modules.dep: No such file or directory
[root@server  /]#

/sbin/modprobe tun is the correct form of the command. ./sbin/modprobe tun is equivalent if the current directory is /

Unless tun is built into the kernel then the problem is that it is not available as a loadable module. IDK RedHat so do not know how to resolve that. How about a new thread asking how to load tun in RedHat (and giving the RedHat release)?

unminser · 05-09-2010, 11:17 AM

Code:

uname -a
Linux server 2.6.18-028stab067.4 #1 SMP Thu Jan 14 17:06:11 MSK 2010 x86_64 x86_64 x86_64 GNU/Linux

catkin · 05-09-2010, 11:52 AM

Quote:

Originally Posted by unminser

Code:

uname -a
Linux server 2.6.18-028stab067.4 #1 SMP Thu Jan 14 17:06:11 MSK 2010 x86_64 x86_64 x86_64 GNU/Linux

That's the kernel. Do you have an /etc/*release* or /etc/*version* file that shows the version/release of RedHat? With that information we should be able to netsearch for how tun is normally set up. The fact that you have a /dev/net/tun file suggests it's in there somewhere.

unminser · 05-09-2010, 11:57 AM

im new to linux i thought uname -a give the system inofrmation

Quote:

CentOS release 5.4 (Final)

mselvaprakash · 05-29-2011, 03:00 AM

Please refer the below URL:

http://unixnethost.blogspot.com/2011...tallation.html