Can receive POP mail, but can't send...what's the deal?

Question

I am trying to set up my school account on my home computer and I followed the directions for the SMTP and POP mail addresses, entered them exactly...and yet, I can't send anything out from Mail using my school address.
What am I doing wrong? Any ideas?

Answer 1

Hi:
Allan has provided some useful information above - specifically -some ISPs block smtp traffic destined to be routed through a foreign smtp server and not THEIR smtp server. As he said, in mail prefs > accounts > schoolAcc't, just use your ISP's smtp server for outgoing mail. The "from" line, as read by your recipients, will still have show your school email address in it, just as you spevcified it when you created that school mail account in Mail.app. The only place junk about the fact that you are actually using your ISP and not your school's smtp server will be in the message header junk that most people don't normally display anyways.
As far as trying an alternate port (587), I don't know about that -- it would seem to me if your school's IT Dept hasn't set up port 587 as a valid port for smtp services, then that would be like specifying port 8080 in your web browser -- typing "http:www.cnn.com:8080" for example -- it won't play.
At my local university, although they would let you login to their imap server (using SSL over port 993) to download mail, they, the university, would not let you send mail if it was originating from an IP address outside of their campus subnet. So all the directions that they gave on configuring your mail account only applied to setting up a computer on campus, not at home.
What I used to do, is, in Terminal.app, log in to the campus via secure shell, and specify some port forwarding options. Then, I modified that Mail (school)account server information to use those particular ports on 127.0.0.1 (localhost), that secure shell would then forward on to the campus network. It was kind of inconvenient, because you had to launch Terminal, login via secure shell, and then launch mail. The upside, however, was that everything between you and the campus mailserver was encrypted. So, can you log into your school's network using ssh?
The first approach above, as suggested by Allan, would be easiest, although if we're talking laptop and you go onto campus, you might have the same issue then because your ISP might not like mail originating from a "foreign" (school subnet) IP address. So, you'd have to be going into Mail's preferences and switching your smtp server depending on which network you were physically affiliated with -- your ISP at home or your campus LAN at school.
If you're interested in exploring the Terminal.app secure shell thing for your mail, post back, I can tell you how to set that stuff up. Depending on your skill level, it could be considered anywhere from easy to moderately difficult to do.