We are looking at replacing our current email setup. At the moment, we have a pair of Clearswift email gateways, with a mimesweeper spam scanning server behind it.
The Email gateways work as a first point to remove obvious spam based on content filtering, virus scanning and ldap queries. Mail then passes on to the mimesweeper for an added layer of spam filtering.
We would like to consolidate these two parts into one. I can see Barracuda and Ironport are the main providers of appliances, but we are open to software based solutions too.
Most important requirements:
-Filtering based on header
-Suitability for 250 users, peak of 700 mails per minute
Looking for recommendations from those that have experience with any solution that may fit.