System Administration & Network Administration
domain-name-system a-record ptr-record rfc
Updated Tue, 27 Sep 2022 19:25:16 GMT

PTR to domain, A record for domain

Does PTR pointing to domain is forbidden? If so - which RFC states that. The same with A record pointing at the domain. As I see, usually, people are trying to avoid such configurations. But I would like to be precise here. Is it forbidden or not. Thanks.

Example: 3600 IN A

and 7200 IN PTR


Your example is completely valid. There is no problem with that at all - it is a very very common configuration.

The main thing you should not do on a domain, but can do on a hostname, is setting a CNAME. This because on the domain name, there will always be NS records and those can never be combined with a CNAME.

Comments (3)

  • +3 – I have found it very useful to use A records for physical hosts and CNAME records for services (such as websites, ftp sites, VPN sites, etc.) In that way I can easily move a service from one host to another and it is visible which host a particular service or site is located on. — Aug 25, 2010 at 12:35  
  • +0 – I do the same, most of the time :) — Aug 25, 2010 at 13:07  
  • +0 – Ok. Thanks for the answer. In this topic I would like to be perfectly precise. @wolfgangsz yes - it is very good habit. Moreover if you have a environement with huge amount of devices, it is good to create additional level of abstraction within domain name scope and have subdomains like: (all web services), (all security services) etc. — Aug 27, 2010 at 09:46