Port 587, Where Have You Been All of My Life?
I spend a lot of time in Starbucks. A *lot* of time. The $19.99/month I pay for my T-Mobile HotSpot account is money well spent. But there is one thing that has bugged me for the past 2 years -- I can receive email all day long (POP and IMAP), but sending email has never worked. I was already using authenticated SMTP with my various mail providers, but that didn't seem to be good enough for Starbucks.
Now, I'm a reasonably smart fellow -- I understand blocking port 25 to avoid the spammers. I could've devoted my meager intelligence to figuring out some sort of clever SSH port-forwarding scheme to get around this. I've read articles about running a SMTP server locally on my PowerBook (which, had I gone to the trouble, would probably have raised *even more* spam red-flags). I'm sure that I could've called T-Mobile tech support, but the thought of the infinite rounds of finger-pointing ("It's Apple's fault. It's Starbuck's fault. It's [insert anyone but our name here]'s fault...") was so unappealing that I couldn't muster the courage to even try it. Instead, I went through the same steps every time: I clicked "send", got the same dreaded "cannot connect to the SMTP server" error message, cursed under my breath, and fired up a web-mail client.
I used Yahoo mail as my primary client for years. But once I got started using Mail.app, the thought of going back is singularly unappealing. (Yeah, GMail as well...) Plus, I've started to depend more and more on Spotlight to retrace my steps. ("I said what? When? To who? What was I thinking?") Doing a non-insignificant portion of my emailing out of band was really beginning to cramp my style.
But what pushed me over the edge was the fact that port 25 was progressively getting blocked in more and more places. Starbucks, hotels, and finally my Mom's Wifi connection at home. Allow me to repeat that in case you missed it: I COULDN'T EMAIL FROM MY MOM'S HOUSE. Something had to change.
Out of desperation, I Googled "apple starbucks send email". At the end of one message thread, someone cryptically suggested changing port 25 to 587. No explanation, and no report back of whether it succeeded or not. I began Googling more: "starbucks port 587", "secure smtp port 587", etc. Apparently, all of the cool kids use port 25 for server-to-server communication and use port 587 for message submission. Allow me to quote RFC 2476:
3.1. Submission Identification
Port 587 is reserved for email message submission as specified in this document. Messages received on this port are defined to be submissions. The protocol used is ESMTP [SMTP-MTA, ESMTP], with additional restrictions as specified here.
While most email clients and servers can be configured to use port 587 instead of 25, there are cases where this is not possible or convenient. A site MAY choose to use port 25 for message submission, by designating some hosts to be MSAs and others to be MTAs.
The RFC is dated December 1998. How did I not know that already? Why has port 587 *never* come up in conversation?
You know what? Never mind. I can send email from Starbucks now. The thought of all of my so-called friends having lengthy conversations about the wonders of port 587 behind my back and then saying, "Shh, here he comes" is too much for me to consider right now.
Posted on Wed, 20 Dec 2006 16:01 by default (1352 day(s) old)
