Symantec Antispam becoming less effective?

It seems in the last few months I am getting much more spam than when we first started using Symantec Premium Antispam in Symantec Mail Security for MS Exchange a couple years ago. Has anyone else seen this? Or is something off in my configuration, though I don't remember making any changes? My licenses are all up to date.

The weird thing is that I am seeing more obvious spam in my inbox, you know the ones that make veiled references to enlarging certain body parts. I can understand a few seemingly legitimate advertising ones slipping through but these are obviously spam.

I do not want to disparage Symantec's products - but I will tell you that I have had better luck with AntiSpam tools that use open source engines as their filter.  SpamAssassin is a very popular one, it can be installed by itself or is often included as a method in professional products.  I've used ASSP (Anti Spam SMTP Proxy) to great effect.  However lately I now use Astaro Security Gateways but those are not free.

As for Exchange, someone posted a very decent link on how to set up Exchange to filter messages.  Its not as adaptive a system as SpamAssassin, but it might bridge the gap of what you're seeing Symantec let through.  Let me see if I can locate the post that talks about how to configure Exchange and if you make those changes you might see a decrease of spam in your Inbox.

I'm sorry, I wasn't able to find the link someone posted about configuring Exchange to filter messages well.  It involved real tiem block lists and the Intelligent Message Filter (which I think isn't so intelligent).  What I did run across however was Rog's post on [ how to configure SpamAssassin to work with Exchange 2003 ].  It's a little old, so maybe he'll come help us out and update it :).