2.5. Turning on Packet Forwarding

2.5. Turning on Packet Forwarding

In order for the LVS router to forward network packets properly to the real servers, each LVS router node must have IP forwarding turned on in the kernel. Log in as root and change the line which reads net.ipv4.ip_forward = 0 in /etc/sysctl.conf to the following: 

net.ipv4.ip_forward = 1

The changes take effect when you reboot the system.

To check if IP forwarding is turned on, issue the following command as root:

/sbin/sysctl net.ipv4.ip_forward

If the above command returns a 1, then IP forwarding is enabled. If it returns a 0, then you can turn it on manually using the following command:

/sbin/sysctl -w net.ipv4.ip_forward=1


Note: This documentation is provided {and copyrighted} by Red Hat®, Inc. and is released via the Open Publication License. The copyright holder has added the further requirement that Distribution of substantively modified versions of this document is prohibited without the explicit permission of the copyright holder. The CentOS project redistributes these original works (in their unmodified form) as a reference for CentOS-4 because CentOS-4 is built from publicly available, open source SRPMS. The documentation is unmodified to be compliant with upstream distribution policy. Neither CentOS-4 nor the CentOS Project are in any way affiliated with or sponsored by Red Hat®, Inc.