forfront security & ESET Mail redundant???

What is the difference between ESET Mail Security and Microsoft Forefront?
Do I need both on my Exchange 2010 Edge server?

 

You would not install both products at the same time, because they are both antivirus products.

ESET Mail Security for Microsoft Exchange Server provides antivirus protection for the server file system, as well as antivirus, and antispam protection for email, via the transport service, and VSAPI for Exchange.

It is not compatible with any other antivirus solutions, including Microsoft Forefront.

Here is some additional information from the ESET web portal:

ESET Mail Security for Microsoft Exchange Server gives you fast, light, and accurate proactive protection for email traffic and mail store. It protects against trojans, viruses, worms, spyware, adware, phishing, spam and other attacks on Microsoft Exchange Server 5.5 to 2010 and Microsoft Small Business Server 2003 to 2011. Our antispam technology uses several complementary processes to ensure total email protection and is configurable using global or mailbox-specific rules. It supports 32- and 64-bit Windows and virtualized environments with quick installation and easy administration.

http://go.eset.com/us/business/server-security/exchange-mail/