Flashes of Panic

Or, Why I Can’t Send E-Mail.

I’ve been struggling lately with one of the hang-ups of mobile computing. In addition to home, where I am the network admin (and, therefore, know the answers to relevant questions,) in the course of most days I open the laptop and go online in several different places. I’ll use the campus wireless network in several buildings (the library, the computing annex, the CS building,) or, in some contexts, I’ll actually plug in to an ethernet cable. The downside of this is that I am actually bouncing between at least four networks: my own, the University wireless network, the University wired network, and the EE/CS network (wired or unwired.)

Now, in this age of spam, one of the strategies used by network administrators to cut down on spam going out of their network (presumably originating from zombies on the network,) is to prevent all machines on the network from sending mail, except through an approved server. This server can be audited, or perhaps require password authentication; the idea, in any case, is that it’s a choke point for outbound email from the network, which makes it easy for the network administrator to shut down a spam source.

You’re already familiar with this if, for example, you have your own mail server (as I do on the flashesofpanic.com domain) and you have broadband internet service from a company like Comcast or Verizon. Those companies force you to use their mail servers, even though the mail you send is coming “from” your own domain.

Now, as one of my professors says, you may be beginning to see the game. Many people never notice the problem because they use webmail almost exclusively; since webmail is entirely http or https traffic between the user and the webmail server, it doesn’t matter which network the user is on. The mail traffic using the SMTP protocol (usually on port 25, for those keeping score,) originates at the web server, not where the user is signed on, so the port 25 restrictions don’t apply.

In my case, I have four different email accounts which I check with any regularity. Three of them have webmail, but it’s about fifty times easier to let Apple Mail handle all four. However, that means the SMTP traffic—outbound mail on port 25—originates with me. As I move around from home to classroom to lab, I shift between networks which have restricted port 25 traffic to three different outbound servers. Sending email became an exercise in frustration.

What I’ve finally ended up with is a variant of the webmail workaround: I’ve taken my outbound email off port 25. I found a few outbound servers which accept an encrypted SMTP connection (using SSL) at a different port. (The port number varies at the mail admin’s discretion, but the default is in the 49x range.) I need a login and password, but I need that anyway to pick up my mail for that account, so there are no worries there. Since most networks are blocking port 25, I can use these mail servers from multiple networks without having to change my outbound mail server every time I open my laptop.

Now, if all this made zero sense to you, let’s look at it in terms of real mail. Imagine mailboxes as servers: most people have two, the box at their house where they receive mail, and some drop box on the street or at the post office where they send mail. (Let’s pretend, for this metaphor, that the postman won’t pick up mail you leave in your box.) Now let’s imagine that junk mail has become such a problem, with people stuffing bundles of the stuff in every blue drop box, that the postal service has decided to crack down: you can only send mail at post offices where the desk clerks recognize you. Now we’ve created a sort of special drop box, perhaps one with a key, which you can always reach.

Still, the fact that we had to come up with this system is immensely annoying. It’s incredible the degree to which the spammers have ruined a previously useful system.

Now Playing: Wild Horses by The Sundays