VLANs and DNAT

[Damien Mason <kinetic@suse.net.au>]

Hi Everyone,

    I have two interfaces, eth1 and eth2

    I have multiple vlans on a eth1, that is, eth1.1 and eth1.2, eth1.3

    Eth2 is the external interface to the internet.

    Vlan1 uses the following network address:    192.168.50.0/24
    Vlan2 uses the following network address:    192.168.50.0/24 also

    Vlan3 uses the following network address: 192.168.10.0/24

I have NAT working for the vlans, that is, clients are able to access 
the external internet using nat.

    However, there are servers on Vlan2 which I would like to forward 
traffic to from the external interface, I would imagine that I could do 
something like:

iptables -A PREROUTING -t nat -p tcp -d 203.221.181.27 --dport 80 -j 
DNAT --to 192.168.50.10:80

But I cannot specify an interface -i eth1.2 in the prerouting, because 
it occurs pre-routing?

    How can I forward traffic to a host on a vlan when the vlans don't 
use unique addressing schemes?.. I was thinking I may have to -j 
REDIRECT the traffic to another chain, and forward it from there?

    Any Ideas or solutions would be most appreciated :)

Thanks in advance,
    Damien Mason



-- 


Best Regards,

Damien Mason
SuSE Systems Specialist

SuSE Linux Asia-Pacific
2-6 Waltham Street
Artarmon, NSW 2064, Australia

Telephone: (612) 943 943 94 ext 246
Facsimile: (612) 9437 3839
Email: kinetic@suse.net.au 
<mailto:kinetic@suse.net.au?subject=Reply%20Email>
Web: http://www.suse.net.au./