I setup a website for a customer a short while ago.

As part of the handover, I setup (and test) his outlook express, so that it can receive emails from his new email addresses (from his new domain).

Two weeks later, he calls and says he can no longer send and receive emails using his new email address.

I try some over the phone troubleshooting, but I have no success. I figure its either a changed setting in OE, or a changed setting on the email section of the website control panel (cpanel). I setup my mail client to read and send his emails, and it works perfectly.

At this stage, its now looking like a problem with his PC, so I make an appointment to visit, and sort out the emails.

When I get there, I find I can receive emails, but sending emails give an 0x00ccc0e error. I do some research and re-enter all the mail server info, but no go. I eventually have to say “I need to check a few things and get back to you”… This is very baffling. I also setup logmein, so that when I have a solution, I can fix it from the office.

Back at the office, after a lot of reading forums and “refining” my google searches, I eventually realise whats going on: Optus (customers ISP) is blocking the outgoing port 25, to anything other than their own mail server.

The confusing part is they allowed it for a while, before blocking it.

There are two solution:

1. Ask Optus to unblock port 25 (which isn’t a big deal and apparently they usually do it without too much hassle)
2. Setup OE to use the optus outgoing server, and setup OE so that emails appear to come from the new email/domain, and the return/reply address also use the new email/domain.

I decide option 2 is the quickest and easiest. After explaining to my customer, he agrees.

So I login remotely, setup OE, test, and everything works well.

Something I need to remember in the future!