[rhelv6-list] weird behaviour of an application when a network interface has 2 ip-addresses

[Masopust, Christian]

On 28 October 2011 12:20, Mezei Zoltan <mezei.zoltan at gmail.com<mailto:mezei.zoltan at gmail.com>> wrote:
On Fri, Oct 28, 2011 at 12:44, John Haxby <john.haxby at gmail.com<mailto:john.haxby at gmail.com>> wrote:
> iptables -t nat -A POSTROUTING -p udp -m udp --sport <host-ip> -p 371 \
>      -j SNAT --to-source <license-ip>:371

You should use the OUTPUT chain in the nat table for this purpose,
otherwise, correct.


Even when  I corrected the "--sport <host-ip> -p 371" to "-s <host-ip> --sport 371" it failed.

# iptables -t nat -A OUTPUT -p udp -m udp -s 192.168.1.1 --sport 371 -j SNAT --to-source 192.168.1.2:371<http://192.168.1.2:371>
iptables: Invalid argument. Run `dmesg' for more information.

# dmesg | tail -1
ip_tables: SNAT target: used from hooks OUTPUT, but only usable from POSTROUTING
________________________________

I found my solution:  a simple "iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to <license-ip>" is doing
exactly what I want!!

Thanks a lot for all your help!
Christian
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