A Blog

It appears that a lot of the people I talk with on campus don’t really get how email is routed. So, I’ll take a short moment to write out how much I’ve gathered.. When someone out on the wild internets sends a message towards an @purdue.edu address, that message lands on the forward facing mail cluster. That cluster determines where the mail must go and sends it along. There are generally two places most mail gets routed to: a Mailhub account or an Exchange account.

The Mailhub group runs most of the mail infrastructure on campus. They do the mail clusters, mail filtering, webmail and standard email accounts. Once mail leaves the incoming servers and is headed towards a Mailhub account, it’ll get filtered and delivered to a back-end storage server where that person’s email address resides. Most students and new staff will have accounts on this set up and they’ll get a standard IMAP account. These accounts are limited in storage (250MB) and have no real mail filtering and only minimal SPAM filtering. Most students just use the really ancient webmail client to get to their university mail and then use a free service for the rest of their email.

How do people use departmental mail servers or Exchange? That’s the interesting piece of the mail system. On campus there is an “account maintenance” system that keeps passwords, machines where a person can login and whatnot. It also stores for people a “mailhost” setting. The Mailhub group nightly pulls that setting and generates an table. If my login name is “bloob” and my mailhost is set to garble@foobar.dept.purdue.edu, then when a Mailhub cluster gets mail destined for bloob@purdue.edu, they’ll send it along to garble@foobar.dept.purdue.edu. So, for people with Exchange, their mailhost setting will be bloob@exchange.purdue.edu.

Now comes the tricks one can play.. Say the limited Mailhub account isn’t for you and no department will sponsor a regular student for an Exchange account (like anyone actually wants one of those…) One can set their account’s “mailhost” to forward their Purdue mail to any valid email address out on the Internet, like gMail. One can either log into a real UNIX server on campus and run the “mailhost” command or use the old directory tool to change their service to “forward”. Once that change takes affect, all your Purdue mail will head to your gMail account. (Obviously, once all this happens, Purdue doesn’t keep a copy of your mail and can’t help in any way if gMail loses your mail!)

Also, say a staff member gets stuck with an Exchange account.. Since Exchange accounts and mail routing are separate, he or she is always able to change that setting while still keeping the Exchange account. Although, because ITaP’s Exchange is terrible, one can never truly rid themselves of it. So, the best solution that has been suggested is to forward mail to a different account and set something like “fetchmail” to routinely go grab new Exchange messages. (Gmail is also able to grab mail from other accounts, but then it also gets a copy of your Purdue password.)

Personally, I forward all my Purdue mail into my own email system which drops a copy onto one of my servers and sends another copy into my gmail account which I use for all my day to day email’ing excitement.