[CentOS] routing with 2 public ips

Fri Dec 25 20:28:03 UTC 2015
Paul R. Ganci <ganci at nurdog.com>

On 12/25/2015 12:44 PM, Joey wrote:
>
> i have a server with 2 public ips on 2 devices.
>
> I want that the request of incoming traffic dont use the default 
> gateway. Incoming traffic sould be answered using the gateway of the 
> incoming device
>
> Could i realize this with firewalld? Or directly iptables?

No you can not do that via firewalld or iptables. The problem is you 
have to tell the packets to go out the proper interface which must be 
done via routing tables. For that purpose you need ip route. I suggest 
you take a look at

https://kindlund.wordpress.com/2007/11/19/configuring-multiple-default-routes-in-linux/

This link provides a very thorough description of what must be done.

Just a warning is that you will want your routing tables to be 
maintained across system boots. I put my routes for my bridged 
interfaces into:

/etc/sysconfig/network-scripts/route-br1
/etc/sysconfig/network-scripts/route-br2

You can put your routes into similar files... just replace the br1/br2 
with your appropriate interface names.

-- 
Paul (ganci at nurdog.com)
Cell: (303)257-5208