Minimising backscatter from your office server

A minor point for system administrators using GreenNet as an outgoing server. Consider the following situation: spam and viruses come directly to the first MX record (in other words, the primary mail server) which is your Exchange server* (*other office mail servers are available).  Your mail server may be configured to accept the message intitially and then bounce it when no mailbox is found or it is blocked (which is bad practice as the bounce is likely to go to a faked sender address).  Sometimes this may even include a live piece of malware. 

If these bounces are set to go out through GreenNet, we'll filter out some malware and spam from these bounces, but the process isn't perfect, and it's much better to prevent the backscatter being sent in the first place.  We don't want to be seen as a source of unwanted and confusing bounces.  One way of preventing the backscatter is to have GreenNet as the first MX and so take advantage of our spam filtering service.  That way you receive less spam, and there's less to bounce.