[CentOS] Addressing outgoing connections to a specific interface

Sat Nov 6 18:51:48 UTC 2010
Lamar Owen <lowen at pari.edu>

On Nov 6, 2010, at 9:04 AM, Dotan Cohen wrote:

> Both connections have router on  the 192.168.0.1
> address.
>
> Although I need to stay connected to the wireless router, can I still
> access the address 192.168.0.1 on the wired interface?

What you want is a NAT to take, say, 192.168.1.0/24 and translate it  
to the eth0 192.168.0.0/24 network, where the translation occurs at  
the egress of eth0 (that is, the 192.168.1.0/24 route is set to go out  
eth0, and the egress (and by extension the ingress) traffic gets  
translated.

How you would do this in iptables I'm not sure; I've done it with  
Cisco hardware, as this is a common issue when joining two RFC 1918  
networks together that have overlapping address space.

But at the end you would access 192.168.1.1 and it would get  
translated to 192.168.0.1 at the eth0 point and wouldn't interfere  
with the wlan0 version of the 192.168.0.1 address.  I'm not exactly  
100% sure it can be done without an external NAT box, but a small  
external router that can do NAT would make it much easier.