Sysctl: net.ipv4.ip_forward
This sysctl key defines if a system should allow forwarding of IPv4 network packets. This functionality is required for systems that act as a gateway or router.
IP forwarding is normally not required for most desktops and servers.
Values
| Value | Description |
|---|---|
| 0 | Forwarding of packets is not allowed. |
| 1 | This system may forward packets to other networks |
Most systems have by default net.ipv4.ip_forward set to value 0.
Show current value
The value of the net.ipv4.ip_forward can be retrieved using the sysctl command.
sysctl net.ipv4.ip_forwardor using the proc file system:
sysctl /proc/sys/net/ipv4/ip_forwardConfigure new value
To apply a new value, use the option --write, followed by the key and value.
sysctl --write net.ipv4.ip_forward=NEWVALUETo ensure that these changes are also applied during the next boot, add them to a configuration file, typically something like /etc/sysctl.d/99-custom.conf.
