redirection ports using webmin

[wclune]

Hello All, not sure if this is the correct forum to ask this question so please forgive if it is not.

I have a few mail server that i want/need to continue managing with webmin. these servers have been running fine for quite a while. iptables is configured to allow needed ports and block the rest. but now i need to redirect port 25 to 2025 for any one coming from any where other than my filter server but still stay on port 25 from my filtering server. Darn spammers are cheating and skipping the MX records.i have not been able to come up with a solution that allows for both. easy to do with a sonicwall or a pix but i cant aquire them now.
any help would be greatly appriciated.

[wclune]

this is what i need to add
iptables -t nat -A PREROUTING -p tcp --dport 25 -i eth0 -j REDIRECT --to-ports 2025
of course many of you know that but going crazy trying to add that in webmin.

thanks again.