Scott Davis has made an important discovery 
about SMTP ports. As a result, he no longer has to choose between email and coffee.
Setting his outgoing SMTP server in Mail.app to use port 587 means that he can now knock back his lattes at Starbucks and send emails at the same time.
The breakthrough came after years of frustration. He didn’t want to sacrifice the beauty of Apple Mail for a web-based service that would have provided him with a work-around for Starbuck’s blocked port 25:
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.
Gmail may not be the answer, but Google was his friend:
… 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.
Gmail offers port 465 with SSL for its smtp.gmail.com server, although it rewrites the from address on any email sent that way to identify you by your Gmail address, unless you set another email address as your default in Gmail’s settings (see more on this at Lifehacker). Not always a good look.
Fastmail offers port 26 and 465 with SSL as work-arounds.
.Mac likes port 587.
Your ISP might offer a way to extend your stay in Starbucks too.
Rogers (Canadian Cable ISP) also uses port 587, which was the method i used for the longest time, before deciding to stop fighting against using my mac.com address (since the .Mac WebMail forced me to use it anyway, I decided I might as well be consistent). I now use the .Mac SMTP servers on 587.
The problem with .Mac, of course, is that you cannot send mail through their SMTP servers unless it carries your mac.com address in the FROM line.
Most ISPs and businesses have now taken the steps of blocking port 25 as a defence against spam-bots and e-mail viruses, most of which still try to propagate their ilk using port 25. Unfortunately, it’s likely only a matter of time before 465 and 587 suffer the same fate….
It is unlikely that a net provider will block ports 465 and 587 as these ports are specifically intended for submission of email via your ISP’s server, not for general server/server email communications. (The latter is what is exploted by the spammers) An email provider that offers SMTP service on said ports normally has them configured such that only authenticated users (i.e., their customers) can send via those ports. In addition, they will often rewrite the FROM so you can’t masquerade as someone else. Consequently, these port are normally useless for spammers (unless the email provider has foobarred their installation). Look at RFCs 2476 and 4409 for technical background on the use of these ports.
While I understand the point of blocking port 25, it is somewhat silly the way it is usually done.
Many people at our office use Bell Sympatico and when they started blocking port 25 I wrote a letter to them complaining about it. You see the problem was, my users needed to be able to send email from their corporate addresses from their home systems. The sympatico solution was to use THEIR email servers on port 25 (which are not blocked).
So basically Sympatico’s mail servers are an open relay if you are on their network – they will happily send email To any address FROM any address.
And they think that this is a good thing.
I tried to explain to them that SMTP authentication and SSL is a better way to fight spam but they just aren’t interested.
The solution? Well since I manage the corporate SMTP server I just opened port 30 for SSL – my server DOES use authentication and ssl so there is no risk of being an open relay – and since Sympatico is only blocking port 25 our staff can access it without problems.
I think it makes a lot more sense to prove you are a legitimate user before you can send email rather than just blocking ports.
Same situation for me… for better than a year I would sit in frustration trying to email from starbucks…
Different solution though!
I had to set mine to use port 80… that did the trick for me.
With Postfix Enabler and MailServe you have been able to do it for quite some time now.
http://cutedgesystems.com/software/PostfixEnabler/
http://cutedgesystems.com/software/MailServe/index.html
Blocking port 25 for most end user connections is a good thing – port 25 is for server to server mail comms and was never intended for end user mail injection.
Port 587 (MSA) is specifically designed for end user mail injection and is specified as TLS encrypted and authenticated – there is therefore no good reason for ISPs to block that port as its not a botnet spam source.
Fastmail has server proxies that can be accessed through any port. I’ve found port 80 and 463 (http/https ports) to be useful in the past.
Look for proxy in the fastmail faq:
http://www.fastmail.fm/docs/faqparts/ExternalMail.htm
Personally I use port 26 for all my smtping needs. However I haven’t ever tried SMTP over SSL…
I agree. In many cases port blocking is just shooting yourself in the foot. Authenticating seems like a better solution to me.
While I agree with the points about the intended purpose of 587 et al, the reality is that there are some ISPs and other mail providers who are now providing connections on those ports as virtually open relays, operating under the assumption that since it’s not 25, there is no risk.
I agree completely that SMTP authentication should always be required for mail injection, but unfortunately there are still too many fly-by-night operations and large monolithic opinionated ISPs that refuse to understand or accept this.
For this reason, more and more corporate firewalls are now blocking 25, 26, 465, and 587, on principle alone. Further, although ISPs like Rogers provide their own SMTP servers on 587, they’re still blocking access to anybody else’s on these ports from some subnets. I’ve also stayed in more than a few hotels that only provide their own SMTP server, and block all other well-known SMTP injection ports.
So while I agree there’s little reason for ISPs to actually block these other ports, it doesn’t change the fact that they are doing it.
(As an aside, however, the fact that Mail.app so easily lets you choose alternate SMTP servers on-the-fly has been a godsend for situations like this)
Strange that I was just at Starbucks today and they (tmobile) seemed to be blocking Port 587. I’ve previously been using Port 587 at Starbucks for as long as I can remember and it has always worked. Please tell me this did not just start today, lol.
I was always taught that 2525 was the alternate SMTP port. It’s good to make note of alternatives just in case!
Thank you so much. I’ve mildly bothered for about 5 years by this. Never enough to spend too much time on it, but definitely a problem. I got a new laptop and this is what pushed me to figure something out. 2 hours later and 1 simple solution better!!