Port forwarding fails

Issues related to configuring your network
Toasty
Posts: 2
Joined: 2018/01/01 15:32:29

Port forwarding fails

Postby Toasty » 2018/01/01 15:57:01

I created a question on Server Fault the other day about this issue (https://serverfault.com/questions/890195/centos-7-fails-to-forward-port), and it contains details on my setup and troubleshooting attempts.

In short, I have two servers running Centos 7. One is up to date and failing to forward ports, and the other is about four months behind on updates and forwarding without issue. The first server can forward ports locally, but forwarding to another IP address on the same subnet fails. The second server does not have this issue.

I've verified that ip_forwarding is enabled on all interfaces, I've tried setting SELinux to permissive (even though nothing was showing in the audit logs), and I've tried running an older kernel (specifically, the same version on the server which is without issues). I haven't tried rolling back firewalld to an older version yet, but I have verified that the iptables rule generated by firewalld is being hit (packet counter increases when I try to send packets to the port in question).

Can someone out there help give me some insight into what might be happening here?

Toasty
Posts: 2
Joined: 2018/01/01 15:32:29

Re: Port forwarding fails

Postby Toasty » 2018/01/02 16:54:42

In case someone else comes across this, I solved my problem by setting the target for the internal zone to 'ACCEPT'.