[exim] sudo - iptables trick

Trying a load reduction trick which I will share if it works. Running
into a little snag and this is probably simple but I need to get user
mail to run iptables that requires user root to run, and without havinf
to use a password to do it.

I'm lazy so is there someone who can tell me what I need to do and I'll
share the trick.

Basicly my idea is that when a dictionary tack occurs I want to block
the IP address for a short period of time as a load reduction trick with
the chain being cleared every few minutes.

Thanks in advance.