reverse dns configuration for IPV4, IPV6+ dns+ mail ?

Reindl Harald h.reindl at
Mon Jun 19 13:32:16 UTC 2017

Am 19.06.2017 um 15:25 schrieb Matus UHLAR - fantomas:
>>>>>> * smtp_helo_name of your MTA matches the same name
>>> this one is incorrect and my next comment applies only to this one:
> On 19.06.17 15:14, Reindl Harald wrote:
>> does it harm? NO
>> is it easy to achive? YES
>> can it be used for scoring on a spamfilter? YES
> is it required? NO.

so what - is FCrDNS required? NO
is it best practice? YES
can it be used for scoring on a spamfilter? YES

>> FRANKLY i have seen enough *real world* postfix rejects caused by 
>> "check_reverse_client_hostname_access" because the idot on the other 
>> side had "" AND the old 
>> "my-provider-xx.xx.xx.xx-dyn.crap" PTR where one time 
>> "check_reverse_client_hostname_access" was fine because it dealed with 
>> the "" and the next mail was rejected by match 
>> "my-provider-xx.xx.xx.xx-dyn.crap"
> those rejections were NOT caused by having two different PTRs.
> They were caused by something different that is not a subject of this
> thread - even one PTR of this format would cause rejections.

not directly but by the fact that someone was smart enough to reqest a 
sane PTR and nother one was not somart enough to remove a useless one, 
by just follow "1 IP has exactly 1 PTR - period" that never would have 
been possible

>> in all of these cases just remove the old useless generic PTR would 
>> have solved the problem from the start
>> so please inform yourself and do tests.....
> go reread the OP's question. He asked about "ns" and "mail" records.
> there's no need to comment something noone did propose

since DNS don't care about the PTR but mail does what is your problem 
that you need stupid dicussions instead just agree that it can't do harm 
and in doubt is beneficial to have just one hostname, use that one 
hostname in helo_name and have just one PTR pointing back to that hostname?

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