At 11:36 pm +0200 13/6/2007, Rolf E. Sonneveld wrote:
Hi,
today I got the following mail from Postmaster at getronics.com
(Getronics being an ICT company with many thousands of employees,
spread over several countries):
<quote>
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 4.5.4.1 "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).
<snip>
Section 4.5.4.1 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.
Glenn.