This is under Debian, but it shouldn't be too terribly different on Redhat.

The default iptables config doesn't allow you to ping ethernal IPs, internally. For example, if I ssh into the server, I can ping localhost, but not any of the server's IPs. I've spoken to a few people and they say this is the older method of anti-spoof protection, and there's better ways that will still let me access my IPs (For reference, I need to be able to use the IPs for a monitoring service)

Its been described to me that I need to setup IPtables to allow internal ips to ping external ips, if using an internal interface, but others continue to deny access. I don't know how to make this change to IPtables though, and I'd really rather not accidently shutdown all access to my server playing with it.

Any suggestions?

Check the rules for the loopback interface. I found that if you have these rules:

you can't ping any of the ips on the server. If you change them to this:


then all of them respond.

Let me know if this helps, I don't use debian so I have no idea what the default firewall looks like.