[Mailman-Users] Queue problems

[Jaco Kroon]

Allan Odgaard wrote:
> On 17 Jun 2008, at 18:53, Mark Sapiro wrote:
> 
>> Brad Knowles wrote:
>>
>>> On 6/17/08, Allan Odgaard wrote:
>>>
>>>> I transferred a lot of list members from a previous list. A dozen of 
>>>> these
>>>> has left errors like the following in `logs/smtp-failures`:
>>>>
>>>>    delivery to <<address>> failed with code 450:
>>>>    4.1.2 <<address>>: Recipient address rejected:
>>>>    Domain not found
>>>
>>> You're doing DNS validation on your outbound
>>> mail.  Don't do that.  Pay attention to the stuff
>>> in section 6 of the FAQ, especially including
>>> 6.6, 6.8, 6.12, etc....
>>
>> Also, fix your MTA configuration so it returns a 5xx status, not a 450
>> for a non-existant domain.
> 
> To the best of my knowledge, this can not be “fixed” (for Postfix). If 
> Postfix is unable to obtain DNS settings for a domain, it will treat it 
> as a temporary error, and will return 450, regardless of settings (and 
> to me this seems correct, as not being able to obtain DNS settings is 
> likely because something is down).

Unless you get an authoritative NXDOMAIN, in which case the domain does 
not exist.  Period.

> If on the other hand it _does_ find a name server for the domain and 
> there is no MX record, _then_ can it be treated as a permanent error.

NOT TRUE.  The RFC states that in the case of no MX record the domain 
name itself should be treated as the only MX record.

> If others should run into this problem `reject_unknown_recipient_domain` 
> was the setting I had to disable in Postfix’s 
> `smtpd_recipient_restrictions`.

Oh.  Not normally a good idea, but in this case I'd agree.  With exim I 
simply accept everything being injected with the sendmail command (as 
well as connecting from localhost but destined for a non-local domain), 
which does something a little different from this, but works very well.

Jaco