ISP port blocking practice

Fri Oct 23 00:38:30 UTC 2009

On Thu, 22 Oct 2009, Lyndon Nerenberg (VE6BBM/VE7TFX) wrote:
> My experience is that port 587 isn't used because ISPs block it
> out-of-hand.  Or in the case of Rogers in (at least) Vancouver, hijack
> it with a proxy that filters out the AUTH parts of the EHLO response,
> making the whole point of using the submission service ...  pointless.

You mentioned this last June.  Can anyone else corroborate it?  Rogers 
says they don't do that, and lots of other people seem to be able to
use port 587 on Rogers (and other ISPs) without problems.

All the cases I've looked at, where someone claimed an ISP was blocking 
port 587, it turned out to be some other problem.  The most common reason 
was related to some security software/host based firewall running on the 
user's own computer.