>> port redirection <<

[Jonathan]

Hi there just a question on port redirection.

I have about 5 ip number bound to the external nic card of my firewall and I
am redirected to 5 different machine inside the firewall.
I can do this
 iptables -t nat -A PREROUTING -p tcp --dport 25 -s 192.168.1.1/32(client
machine in the web) -j DNAT --to 192.168.2.1:25(mail server inside the
firewall)
but the above will only allow 192.168.1.1 to send mail to the ONE mail
server but I still have 192.168.2.2 , 192.168.2.3 , 192.168.2.4 ,
192.168.2.5.

I do this with ipmasq lik this
ipmasqadm portfw -a -P -tcp -L 209.212.100.1 25 -R 192.168.2.1 25
ipmasqadm portfw -a -P -tcp -L 209.212.100.2 25 -R 192.168.2.2 25
ipmasqadm portfw -a -P -tcp -L 209.212.100.3 25 -R 192.168.2.3 25
ipmasqadm portfw -a -P -tcp -L 209.212.100.4 25 -R 192.168.2.4 25
ipmasqadm portfw -a -P -tcp -L 209.212.100.5 25 -R 192.168.2.5 25

how do you do the above with iptables ?

thank you
Jonathan