Spam Filtering - Appliance vs. Filtering Service

Echoing Kevin, if you have a small amount of employees, go with Postini.  It pays for itself very, very quickly.

If you are using barracuda currently then keep using it and use positni along with it. This will give you double layer of spam filtering.

I looked at postini but i ended up using mxlogic i have to say that this was a good move
http://www.mxlogic.com/services/index.cfm

I honestly would not use hardware the least hardware that i have to monitor the better.

The least hardware is the better, it's right, if you will be the one who monitor your hardware. However, if you have a crew of 10 people sitting there and wait for new tasks or projects and you are the manager who assign them the task --> the more hardware is the better (more controls and creditibilities). So you play the show of picking the right solution for yourself.

K

I agree with lnkevin.  

It's always nice having a 3rd party do it though, as it effectively creates a relay for you.  Then you can further protect your network by blocking inbound port 25 traffic to only the service provider's IP address.  This is critical in preventing someone from remotely pulling your smtp banner and enumerating/footprinting your mail server.  Often the banner reveals the server's entire life history including time zone and patch level.

You can also modify the banner on most mail servers, which is not a bad idea.
http://support.microsoft.com/?kbid=281224

Postini isn't the only game in town. Frontbridge was acquired by Microsoft to become Microsoft Hosted Filtering
http://www.microsoft.com/exchange/services/filtering.mspx

Our company of over 4000 users has outsourced our spam filtering to our ISP, combined with Exchange spam filters, and it has proven to be very cost-effective over maintaining appliances and other systems in-house.

At present, our ISP does our spam filtering.  They use SpamAssassin: http://spamassassin.apache.org/.  It does a decent job.  It scans the email based on certain rules, and anything that scores above a specific score is directed to the spam mailbox where one of the help desk individuals gets to sort through (10 minutes, tops, a day).

We have a nice multilayer approach.  I have a TSP (tech service provider) scan for viruses on their systems, then forward to spamsoap for spam, then to our perimiter where our Intrusion Prevention System analyzes it, then our mail server AV & spam, then our client AV, and finally our employees and their common sense.  The 2 service providers total less than $800 annually.  And as said before, it allows for blocking port 25 traffic to only the nearest service provider.  Also if our mail server were to ever go down (hasn't yet, knock on wood), all our mail would be held in queue at our service provider.  I will admit there is no substitute for a manual rule blocking all zip files under 75k (only viruses zip small files).  I have sent about 4 new viruses to avert labs in the past thanks to this rule.