[pfx] Re: I keep getting disabled on [email protected] mailing list

On 15/06/2026 2:29 pm, Fred Morris via Postfix-users wrote:
> Just want to make sure this is what you think it is...
> 
> On Sun, 14 Jun 2026, Al via Postfix-users wrote:
>>>>>>  [...]
>>>>>>  I keep getting disabled on [email protected] mailing 
>>>>>> list. I
>>>>>>  have resubscribed many times.
> 
> I presume you actually queried the list manager to verify your 
> subscription or lack thereof...

Yes, I have.

>>>>>> Is there a problem with my configuration?
>>>>>>  What can I do to fix this?
>>>>> 
>>>>>  You need to stop rejecting mail from the list. That could be 
>>>>> because
>>>>>  you've chose strict DMARC enforcement, which is incompatible with 
>>>>> most
>>>>>  discussion mailing lists.
>>>> 
>>>>  I am not using DMARC.
>>> 
>>>  That makes the situation less obvious.
> 
> ;-)
> 
>>> Examine your logs to find the
>>>  rejections, which should give you a hint as to why they are 
>>> happening.
>> 
>> I have taken a look at my logs:
>> 
>> This is the error:
>> 
>> Jun  9 12:03:41 sequoia postfix/smtpd[52759]: NOQUEUE: reject: RCPT 
>> from unknown[45.90.5.195]: 554 5.7.1 Client host rejected: cannot find 
>> your reverse hostname, [45.90.5.195]; 
>> from=<[email protected]> to=<[email protected]> 
>> proto=ESMTP helo=<list.sys4.de>
>> 
>> However, most of the of the time it lets, it through:
>> 
>> 0.43, dsn=2.6.0, status=sent (250 2.6.0 <[email protected]> Message 
>> accepted for delivery)
>> Jun 14 06:35:36 sequoia postfix/qmgr[83260]: 4DC2D1F5A07: removed
> 
> 45.90.5.195 is list.sys4.de:
> 
>     # dig -x 45.90.5.195 +short
>     list.sys4.de.
> 
> It actually says this in the log message you posted:
> 
>     helo=<list.sys4.de>
> 
>> From this I skull that
> 
>     1) you are checking the reverse lookup and rejecting mail where the
>        result doesn't match what was announced with HELO; and
> 
>     2) reverse lookups are failing
> 
> Where the reverse lookup is failing, I don't know.
> 
> This is probably a good time to ask: do you run a local caching DNS 
> server alongside postfix (or within a couple of hops)? Aside from the 
> Other Important Reasons, if you're not running it locally then you're 
> not going to have logs to refer to; you might try tcpdump, but if it's 
> a sporadic problem it might be a quiet day fishing.

I am running bind9 on the same system. I have looked at everything that 
I can think of, but I am not finding an error.

Kind Regards,
Al
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