It is simple to enable
SMTP (Simple Mail Transfer Protocol) on another port. To do this please follow the step-by-step direction below.
[1] Login to your
WHM (Web Host Manager)
[2] Next Go to the
"Service configuration" section
[3] Locate the row that says
"Exim On Another Port" option.
[4] Please enable the following two
check-boxes.
Quote
Monitor = YES (Checked)
Enabled = YES (Checked)
[5] Once Done, Click on
Save to apply your settings.
Now your cPanel SMTP should start working on PORT 26 rather than just on PORT 25 (Which is blocked by most of the ISP's)
Sometimes it is smart to use port 2525 as Exim alternative with hosting server cause it is really easy to remember.