jsolo1
Premium
join:2001-07-01
| reply to NormanS
Re: [E-Mail] SMTP.rcn.com silently not relaying, again
Norman good point. My response was based on email submission, not transmission. You do bring up a good point though. Not sure how that would work. I imagine there may be a white list of sorts?
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Insanity is living in a state of disillusion. |
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negativeduck
Premium,VIP
join:2002-02-14
Centreville, VA
edit:
May 13th, @05:46PM
| Several mail hosts will not accept unauthenticated delivery requests from hosts that are NOT known isp's, or rather they specifically 'reject' or do not allow communication from a host that "appears" to be a dynamic IP pool connecting to their mail exchangers.. now this is a different scenario than say 'smtp' servers while fundamentally they same they like to serve different purposes.
IE if you run your own mail-server on a standard dynamically allocated IP there is a strong chance that you will never be able to deliver your email to alot of hosts. This is where smart-hosting and smart-relaying come in where you transfer your mail to a larger ISP for delivery to another large entity.
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Bryan Laird
Director Product and Technology |
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NormanS
Premium,MVM
join:2001-02-14
San Jose, CA
 ·Pacific Bell - SBC
| reply to jsolo1
Or read RFC 2476. That is the officially designated message submission port. Also, as a de facto standard, SMTPS (SMTP w/SSL) uses port 465.
Also read RFC 2821. SMTP does not require port 25, except for mail transfer.
If all E-mail Service Providers moved message submission to either the designated message submission port (RFC 2476), or even just any other port than port 25, it would be possible to reserve port 25 for mail transfer. Each gateway mail server can then decided for itself if a connecting mail host is trustworthy (allow), or not (deny).
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Norman
~Oh Lord, why have you come
~To Konnyu, with the Lion and the Drum |
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