While I am still working on new mail servers, I’ve updated postfix on the current incoming servers, mx1 and mx2, and client server mail, to the latest version which is postfix 3.0.1.

     The primary reason for doing this is that it added settings for how long mail could be kept in queue before being rejected.  This was necessary because of people sending mail to domains which had MX records but non-functional or non-existent servers at the IP addresses those records resolved to.  It was also necessary because of sites like Yahoo and Google which sometimes won’t accept e-mail as fast as our servers are trying to send it and, if this goes on too long, causes a backlog in our mail queue.