help with iptables

[John Van Ostrand]

On Fri, 2007-01-19 at 10:56 -0500, Dave Cramer wrote:

> So what I'd like to do is  using iptables :
> 
> 
> route port 25 traffic currently going to B --> A except when it comes
> from A

You have two options. 

If the port 25 traffic that you want to NAT is always coming in from one
interface and system A is on another then use the --in-interface
iptables option to specify the external interface.

If you can't differentiate based on interface then you'll have to go to
policy routing. See iproute2 to create a separate routing table for the
traffic. You may also need to use iptables MANGLE table to mark packets.


-- 
John Van Ostrand
         Net Direct Inc.
 
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