In a previous post I covered how to use DNS tools to find what host receives email, and in this one I’ll cover the recipient part of an email address which is to the left of the @. Exact details on how to control what happens for a particular address depends on the ISP, so I’ll only be covering the topic in general terms.

The straightforward case is when mail just gets delivered into a normal mailbox, which may be the case if you own your own domain. If mail does not get delivered to the mailbox (and you’ve confirmed that the mail is going to the right host) then one possibility is the mail is getting forwarded off to another address. How this gets set up varies greatly, but many ISPs have some sort of control panel you can use to manage email forwarding.

For domains with many recipients (such as @washington.edu) mail is spread across many relays and then routed to the correct destination. Relays can be explicitly listed (as with UW) or things can be done behind the scenes to spread load, possibly with equipment to map a single IP address to multiple hosts. Multiple hosts are used to both increase bandwidth and improve reliability, so if one host goes down others can still handle the load.

Many servers which store mail allow users to filter mail to alternate folders or to forward messages to another destination (for the deskmail service this would be Email Delivery Manager). In addition, many mail clients also allow you to manipulate messages. Whether you use server-based or client-based filtering depends (or both) on which features each offers. Most filters can be set up to either allow processing to continue or to stop if a rule matches.

If you’re having problems receiving certain email messages but are receiving others, the filters are a good place to check. Another would be your junk mail folder, since either the server or your email client could have moved the messages there.

If you’re receiving no messages, checking filters is also a good first step, but you may have to check where DNS is pointing for your domain.