Re: [Emailcore] Ticket #5: G.5. Remove or deprecate the work-around from code 552 to 452?

[Jeremy Harris <[e-mail]>]

On 15/02/2021 13:41, Alexey Melnikov wrote:
>> The first pagaraph of Section 4.5.3.1.10 (Too Many Recipients Code)
>> currently says:
>>
>>      RFC 821 [3] incorrectly listed the error where an SMTP server
>>      exhausts its implementation limit on the number of RCPT commands
>>      ("too many recipients") as having reply code 552.  The correct reply
>>      code for this condition is 452.  Clients SHOULD treat a 552 code in
>>      this case as a temporary, rather than permanent, failure so the logic
>>      below works.
>>
>> John noted that this suggestion may have outlived its usefulness
>> and/or be inconsistent with current practice. Should it be removed
>> and/or explicitly deprecated?
> 
> I did a bit of digging and it doesn't look like Sendmail emits 552 or treats it as 442 if received from other MTA.
> Postfix code has this commented out with a note that this workaround creates more problems than it solves, due to other meaning of 552.
> 
> Do people have information about other MTAs (not necessarily open source) on this topic?

Exim:

  As a server, there is a configuration option (default: 452)
  for too-many-recipients.
  The documentation describing it doesn't mention standards.
  553 is emitted for other conditions.

  As a client, there is no special handling for a 552; the initial
  5 is taken as for any other 5xx.
-- 
Cheers,
   Jeremy