ISP port blocking practice

Fri Oct 23 15:25:56 UTC 2009

On Oct 22, 2009, at 6:14 PM, 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.

We use 587 quite a lot (with SMTP Auth and SSL/TLS), and have found  
_very_ few places block or proxy it.  We don't have any/many customers  
in Rogers service areas though.

The biggest reason people don't use it is that it requires some  
thought and tweaking settings in the "advanced" tab areas of many  
email clients.  Newer email clients are actually starting to look for  
submission port and SSL support and configuring it autmatically if  
they find it.

Once it's set up correctly we've found customers really like it since  
their email "just works" in most places.

--Chris