Re: Exchange server & Web Security for mid size company.... Need advise.

[barcajax () gmail com]

It doesn't hurt to have three layers (gateway, client and email server) because each one serves its own function. The 
gateway solution can inspect web traffic such as HTTP, HTTPS, SMTP and FTP (depending on the solution chosen), the 
email server obviously caters to emails received and sent while the client providing PCs from infection that comes from 
surfing the web or from storage media (diskettes, portable storage devices, infection from other machines within the 
same segment).
Just a note, having three layers provide overlap in securing your organisation BUT get solutions from different vendors 
for each because different vendors provide different response times for new vulns/viruses/worms/trojans. For example, 
McAfee may release a new virus definition to address Blaster first but Symantec may react the fastest for the WMF vuln. 
Three different vendor products for your three layers will increase your chances of having a new sig for a new threat.

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