Sending E-mail via a Third-Party Service
Information Technology Services (ITS) has received reports from UMBS e-mail users who are customers of SBC DSL that SBC is preventing them from connecting to port 25 to send e-mail messages. Many Internet Service Providers (ISPs) prevent their subscribers from connecting to port 25 on remote mail servers to prevent their subscribers from sending spam. Unfortunately, it also prevents legitimate users of remote mail servers from submitting their mail.
You can get around this issue by changing your sending (outgoing) SMTP server from port 25 to port 587. Spammers don't abuse port 587 because mail servers almost always require authentication on that port.
Instructions for changing the port number in specific e-mail programs are included in the instructions for setting SMTP authentication. Find the instructions for your e-mail program.
