[Top] [All Lists]

Re: Question on retry strategy in 2821

2007-06-13 17:22:51

At 11:36 pm +0200 13/6/2007, Rolf E. Sonneveld wrote:

today I got the following mail from Postmaster at (Getronics being an ICT company with many thousands of employees, spread over several countries):

The sending system (IP address <my MTA's IP address here>) apparently retries delivery only every two hours. The intial retry after a 421 status should be less than 30 minutes. Please refer to RFC 2821, section "Sending Strategy", where the recommended first retry should be 30 minutes, and there should be two retries within the first hour. The initial retry after a 421 status should probably be somewhat shorter (say 15 - 20 minutes).


Section of RFC 2821 says "The sender MUST delay retrying a particular destination after one attempt has failed. In general, the retry interval SHOULD be at least 30 minutes;"

"at least 30 minutes" to me means the retry interval should be 30 minutes or more, not 30 minutes or less.

Am I misinterpreting RFC2821 in that (IMO) there is no such requirement as stated here?

There certainly doesn't seem to be any requirement for a shorter retry after a 421 response.

It is not my intention to start a (flame) war on greylisting, but keeping greylist information for only one hour needs a reality check, isn't it?

I don't think their implementation is very robust. The default setting for my MTA is to keep graylisting information for 30 days.

I know at least two mature and well-known MTA implementations that have a default retry interval which doens't match the requirements of this domain.

My MTA defaults to an hour delay to retry, typically that will result in slightly more than an hour between retries, which would not appear to meet the requirements of that domain.


<Prev in Thread] Current Thread [Next in Thread>