Originally Posted by XmisterIS
I would be wary of using barracuda for this. We have had a few runs in with barracuda firewalls in the past. Basically some default barracuda hardware firewalls used a default blacklist which was out of date and it did cause issues back then with some innocent IP's being blocked.
Seems a bit extreme anyway. Its not always bots that are doing the spamming. Recently we saw evidence of manual contact form abuse. It always happened around about the same time of day from the same region. We suspect there are groups of organised spammers out there who are happy to put there rubbish into forms manually.