underscore in A or PTR records

Wed Feb 17 09:41:07 UTC 2021

Matus,

What do you mean with " absolutely no, but since underscore is not valid in hostname as per rfc1123, I don't recomment you to use it in hostnamed" ?

I tried with the following configuration in zone " dekil.nl " and bind do not accept it:

hello_mail2.dekil.nl.         3600    IN      A       81.246.48.28

I have the following message error:

Feb 17 10:40:41 dnszone904 named[1633]: /etc/bind/zones/master/dekil.nl:19: hello_mail2.dekil.nl: bad owner name (check-names)
Feb 17 10:40:41 dnszone904 named[1633]: zone dekil.nl/IN: loading from master file /etc/bind/zones/master/dekil.nl failed: bad owner name (check-names)
Feb 17 10:40:41 dnszone904 named[1633]: zone dekil.nl/IN: not loaded due to errors.

Sensitivity: Internal Use Only

-----Original Message-----
From: bind-users <bind-users-bounces at lists.isc.org> On Behalf Of Matus UHLAR - fantomas
Sent: 17 February 2021 09:53
To: bind-users at lists.isc.org
Subject: Re: underscore in A or PTR records

On 17.02.21 08:13, ONRUBIA AVILES Carlos (CCS/MST) wrote:
>I face the following problem  ==> bind do not accept an A record with underscore:
>
>Example:     example_try   A    1.2.3.4
>
>
>Same for a PTR:
>
>Example:   1.2.3.4   PTR   example_try
>
>
>Is it absolutely forbidden to have in such cases an '_'?

absolutely no, but since underscore is not valid in hostname as per rfc1123, I don't recomment you to use it in hostnamed.

>I know that it is possible for SRV or TXT records.

it's valid in DNS, but not in hostnames.  You can in fact disable checking but you may encounter problems with remote sites.

--
Matus UHLAR - fantomas, uhlar at fantomas.sk ; https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.fantomas.sk%2F&data=04%7C01%7Ccarlos.onrubia.aviles%40proximus.com%7Ce40888443de343c66a9408d8d3218eb1%7Ce7ab81b21e844bf79dcbb6fec01ed138%7C0%7C0%7C637491488366965000%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=KzvQWs%2BuNEwQvNH2rKKOreQlm2YhJfYYPrssbqswhV4%3D&reserved=0
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