IP Forwarding Stopped Working

vijaysoft · 04-13-2012, 07:41 PM

I've a difficult situation here. My ipforwarding setup on a Redhat machine stopped working all of a sudden. I have ipforwarding scripts in place that worked fine till yesterday. I have tried all sorts of configuration but no luck. Can any body explain me what could be the reason for this problem?

fukawi1 · 04-14-2012, 02:15 AM

Was the machine rebooted? Or (possibly) the networking service restarted?
If sysctl isn't configured to enable ip_forward at boot then this could cause the problem.
You can check this with: (1 is enabled)

Code:

# cat /proc/sys/net/ipv4/ip_forward
1

And this link explains the fix. Particularly in the *note* section.

vijaysoft · 04-14-2012, 06:13 AM

Thanks for looking into my issue. I have the IP Forwarding enabled and all settings are intact. Later I found that the issue was due to the reason that my ISP changed DNS numbers. When I changed all those client machines where I had this DNS number specified it resolved the issue.