Does anyone have experience scanning hosts running iptables firewalls running tarpits.

I have come up against a few recently with nmap and i'm wondering whats the best away around them.

Anyone know of any specific options I can specifiy through nmap to help avoid these ports

I thought about just specifying know ports for my scans but that means I would miss any other servers running on non standard ports

Any help would be great

Memnoch