Thanks Brian. You were right.
I was able to ping the server, but unable to telnet to it. So I looked up
my ISP -- not the company that hosts my mail, but the real ISP, the folks who
let the house connect to the internet -- and found that they don't allow
third parties (e.g. my mail host) to use port 25.
Why I'd been able to use port 25 before installing Office's Service Pack 3,
but not after, is a mystery. But it's an academic one: I found the login
and password for the ISP (something I've never used, since we're broadband),
and put those in my "outgoing/SMTP authentication" fields. Now my mail sends
fine, and it still looks like it's coming from my third-party server.
Thanks again.
- Chris
Brian Tillman said:
[...] Open
a command line window and see if you can ping the SMTP server
C:\> ping yoursmtpserver
If you can do that, try telnetting to it:
C:\> telnet yoursmtpserver 25
If you get a response, enter QUIT. You've proven your PC can connect and I
don't have any suggestions at the moment, other than verifying your SMTP
settings. If you can't connect, contact your ISP. Perhaps they don't allow
port 25 connections and you have to use another port.