Jon Fisher

Clients tell us that the most important service that a business’s computers run is email.  When email goes down everyone in the company is affected, as well as their clients.  But what does it take to setup/keep a mail server running?  It can get complex with many different components involved.  You’ve got to have correct networking setup.  Most mail servers have a mail transfer agent (MTA), a POP3 or IMAP server, a spam filtering service, a virus filtering service, a database, and a web interface to get to that mail.  Beside all of the technical details there are three technical aspects that anyone involved should be aware of: a static ip address, access to the mx record for your domain, and an implemented reverse dns record.

1.       A static IP address is the easiest to understand and obtain.  It is an internet ip address that is issued by your internet service provider and if it’s static it doesn’t change.

2.       Often domain names are setup as a company is formed and might not need to be changed very often.  The mx record is part of this domain setup and is the part that handles mail transfer.  Losing your domain credentials or information could prove deadly in a crunch when you really need them.

3.       RFC 1912 suggests that every domain have a reverse dns.  A reverse dns is a way to have an ip address reference a specific domain.  All mail sent from your domain should come from the ip address of your email server.  This is important because MANY spam filters check for these reverse dns and if you don’t have one ,chances are your legitimate mail will be blocked by the recipient.