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Re: acceptings particularly a message (3)

2007-07-19 15:44:12

Robert A. Rosenberg wrote:

At 11:36 -0700 on 07/17/2007, Ned Freed wrote about Re: acceptings particularly a message (3):

A significant number of list managers that receive an
>> authoritative indication that an entire group of
>> addresses they just tried to send to are bad are going to
unsubscribe them all right away rather than wait for
>> a later probe to confirm that the addresses are bogus.

If they are going to want to unsubscribe all the addresses, IMO, they should first sanity check the list by either doing an immediate probe to that list of addresses (and unsubscribe based on the results, thus not unsubscribing the good addresses), or doing individual resends of the message but this time sending one copy per address (in effect doing the same thing as the probe and/or acting as if each address was the only one at that domain/MX).

I believe what Ned as implying was that this "probe" was already done by virtue of the SMTP attempt to deliver the distribution and its recorded HARD FAILURE to deliver the mail to the address and/or domain provides dynamic, immediate and SMTP level feedback to the MLS (Mail List Server) or any one other client.

The next time the MLS connects to its smart host (or embedded SMTP server) to begin a distribution, it will get some 45x/55x for some of the RCPT TO addresses based on the SMTP recorded history for the address/domain. At that point, the MLS will automatically unsubscribe or de-activate the address.

This works because most, if not all, good SMTP servers today will record HARD FAILURES for relays and will have keep a history of the bad addresses. The next time an attempt is made to relay mail to the address, it will issue a negative response. Why accept an RCPT TO when the SMTP server knows the address is bad and can't be routed?

For our MLS system, it makes the account in-active rather than unsubscribe. That gives someone a chance to make any individual corrections and reactivate the account.


Hector Santos, CTO