Re: ISP port blocking practice

Few companies use the MSP port (tcp/587).

Can you elaborate. Is this based on analysis you've conducted on your own network? And if so, is the data (anonymized) available for the rest of us to look at? 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. --lyndon