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

[Pierre Couderc]

On 06/19/2017 01:05 AM, Reindl Harald wrote:
>
>
> Am 18.06.2017 um 17:38 schrieb Matus UHLAR - fantomas:
>> On 18.06.17 16:26, Mark Elkins wrote:
>>> Put two reverse records in both  the IPv4 and IPv6 reverse zones....
>>>
>>> in the "125.124.123.in-addr.arpa" zone:
>>>
>>> 126   IN   PTR   mail.xxx.com.
>>> 126   IN   PTR   ns.xxx.com.
>>
>> while this is possible, it's not always a good idea.
>> One reverse record is enough in most cases you need reverse DNS.
>> (which mostly means, for outgoing mail)
>>
>>> Nothing wrong with a machine (or interface on a machine) having more
>>> than one name for the same address. List them all in the reverse
>>> configuration. After all, a NS record usually has at least two 
>>> records ;-)
>>
>> there are cases when having two reverse records is misleading
>
> it's nearly always misleading and results in randomness on the 
> receiving server which name get logged and if A/PTR matches
>
> normally you should always have:
>
> * IP with *one* PTR
> * the A-Record for the PTR matches
> * smtp_helo_name of your MTA matches the same name
>
This is clear in IPV4 but what about IPV6 ?



If I declare xxx.com bind :

mail A 123.124.125.126
mail AAAA 2a01:e34:xxxx:xxxx:xxxx:xxxx:1122:3344

ns A 123.124.125.126
ns AAAA 2a01:e34:xxxx:xxxx:xxxx:xxxx:aabb:ccdd

What should I put for IPV4 reverse address : if I put mail.xxx.com, the 
reverse address will not point on ns.xxx.com, and if put ns.xxx.com, the 
reverse dns will not point on mail.xxx.com, and I shall have mail problem.