How to enable IP Forwarding in Debian
IP routing/forwarding is disabled per default in Debian.
For enabling on the fly, you only have to write “1″ in /proc/sys/net/ipv4/ip_forward or to set the kernel parameter net.ipv4.ip_forward to “1″.
Method #1: echo 1 > /proc/sys/net/ipv4/ip_forward
Method #2: sysctl -w net.ipv4.ip_forward=1
The actual setting can be checked as following:
debian:~# sysctl net.ipv4.ip_forward net.ipv4.ip_forward = 1 debian:~# cat /proc/sys/net/ipv4/ip_forward 1 debian:~#
If you want permanent setting, the most common way is to add a line containing “net.ipv4.ip_forward = 1″ to the file /etc/sysctl.conf
/etc/sysctl.conf: net.ipv4.ip_forward = 1
You can activate the changes made in the kernel parameter configuration file by running the command:
sysctl -p /etc/sysctl.conf
Perhaps there are some distribution specific scripts available in Debian, but i didn’t check it.