underscore in A or PTR records

classic Classic list List threaded Threaded
12 messages Options
Reply | Threaded
Open this post in threaded view
|

underscore in A or PTR records

ONRUBIA AVILES Carlos (CCS/MST)

Hello ,

 

I face the following problem  è 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 ‘_’?

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

 

 

Thanks in advance to clarify the situation and sorry if this question has already be asked.

 

Carlos,

 


Sensitivity: Internal Use Only

This e-mail cannot be used for other purposes than Proximus business use. See more on https://www.proximus.be/maildisclaimer

_______________________________________________
Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list

ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.


bind-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/bind-users
Reply | Threaded
Open this post in threaded view
|

Re: underscore in A or PTR records

Mark Andrews
The SRV and TXT records usage is depending on underscore not being part of a hostname.
The separator in hostname labels is dash.  e.g. my-host.example.net

_ssh._tcp.example.net SRV can be safely deployed because there are no legal hostnames
starting with _ssh and _tcp.

Hostname (and mail domain) syntax is defined by RFC 952 as modified by RFC1123 (allows
labels to start with digits.

PTR records it depends on usage.

Mark

> On 17 Feb 2021, at 19:13, ONRUBIA AVILES Carlos (CCS/MST) <[hidden email]> wrote:
>
> Hello ,
>  
> I face the following problem  è 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 ‘_’?
> I know that it is possible for SRV or TXT records.
>  
>  
> Thanks in advance to clarify the situation and sorry if this question has already be asked.
>  
> Carlos,
>  
>
> Sensitivity: Internal Use Only
> This e-mail cannot be used for other purposes than Proximus business use. See more on https://www.proximus.be/maildisclaimer
> _______________________________________________
> Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list
>
> ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.
>
>
> bind-users mailing list
> [hidden email]
> https://lists.isc.org/mailman/listinfo/bind-users

--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742              INTERNET: [hidden email]

_______________________________________________
Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list

ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.


bind-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/bind-users
Reply | Threaded
Open this post in threaded view
|

RE: underscore in A or PTR records

ONRUBIA AVILES Carlos (CCS/MST)
Hello,

Thanks for these clarifications.
The issue we face is that a telecom provider ask us to implement a PTR record with a name like "example_try.net"
We tried this configuration but BIND do not accept it.
The telecom provider complaints we can not make this DNS configuration and that it must be possible (for the moment they do not gave us examples to prove what they say).

So to be clear can we answer to this telecom provider that using a PTR with "_" is not possible and not RFC compliant? Or is there anything I miss?

Thanks in advance for your time.

Carlos,


Sensitivity: Internal Use Only

-----Original Message-----
From: Mark Andrews <[hidden email]>
Sent: 17 February 2021 09:28
To: ONRUBIA AVILES Carlos (CCS/MST) <[hidden email]>
Cc: [hidden email]
Subject: Re: underscore in A or PTR records

The SRV and TXT records usage is depending on underscore not being part of a hostname.
The separator in hostname labels is dash.  e.g. my-host.example.net

_ssh._tcp.example.net SRV can be safely deployed because there are no legal hostnames starting with _ssh and _tcp.

Hostname (and mail domain) syntax is defined by RFC 952 as modified by RFC1123 (allows labels to start with digits.

PTR records it depends on usage.

Mark

> On 17 Feb 2021, at 19:13, ONRUBIA AVILES Carlos (CCS/MST) <[hidden email]> wrote:
>
> Hello ,
>
> I face the following problem  è 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 '_'?
> I know that it is possible for SRV or TXT records.
>
>
> Thanks in advance to clarify the situation and sorry if this question has already be asked.
>
> Carlos,
>
>
> Sensitivity: Internal Use Only
> This e-mail cannot be used for other purposes than Proximus business
> use. See more on https://www.proximus.be/maildisclaimer
> _______________________________________________
> Please visit
> https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Flist
> s.isc.org%2Fmailman%2Flistinfo%2Fbind-users&amp;data=04%7C01%7Ccarlos.
> onrubia.aviles%40proximus.com%7Cdf9e40bb2739424445be08d8d31de6af%7Ce7a
> b81b21e844bf79dcbb6fec01ed138%7C0%7C0%7C637491472662614546%7CUnknown%7
> CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXV
> CI6Mn0%3D%7C1000&amp;sdata=o3VYr2m93TRf7ODAq8NPV3M5dd4EvXR9uZ8wdi3C1X8
> %3D&amp;reserved=0 to unsubscribe from this list
>
> ISC funds the development of this software with paid support subscriptions. Contact us at https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.isc.org%2Fcontact%2F&amp;data=04%7C01%7Ccarlos.onrubia.aviles%40proximus.com%7Cdf9e40bb2739424445be08d8d31de6af%7Ce7ab81b21e844bf79dcbb6fec01ed138%7C0%7C0%7C637491472662614546%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=SiZULEaSrJIfUUxXhwwLP%2Fa2Yg3w2pJuJcivH2Wadtk%3D&amp;reserved=0 for more information.
>
>
> bind-users mailing list
> [hidden email]
> https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Flist
> s.isc.org%2Fmailman%2Flistinfo%2Fbind-users&amp;data=04%7C01%7Ccarlos.
> onrubia.aviles%40proximus.com%7Cdf9e40bb2739424445be08d8d31de6af%7Ce7a
> b81b21e844bf79dcbb6fec01ed138%7C0%7C0%7C637491472662614546%7CUnknown%7
> CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXV
> CI6Mn0%3D%7C1000&amp;sdata=o3VYr2m93TRf7ODAq8NPV3M5dd4EvXR9uZ8wdi3C1X8
> %3D&amp;reserved=0

--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742              INTERNET: [hidden email]
This e-mail cannot be used for other purposes than Proximus business use. See more on https://www.proximus.be/maildisclaimer
_______________________________________________
Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list

ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.


bind-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/bind-users
Reply | Threaded
Open this post in threaded view
|

Re: underscore in A or PTR records

Matus UHLAR - fantomas
In reply to this post by ONRUBIA AVILES Carlos (CCS/MST)
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, [hidden email] ; http://www.fantomas.sk/
Warning: I wish NOT to receive e-mail advertising to this address.
Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
Linux IS user friendly, it's just selective who its friends are...
_______________________________________________
Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list

ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.


bind-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/bind-users
Reply | Threaded
Open this post in threaded view
|

RE: underscore in A or PTR records

ONRUBIA AVILES Carlos (CCS/MST)
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 <[hidden email]> On Behalf Of Matus UHLAR - fantomas
Sent: 17 February 2021 09:53
To: [hidden email]
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, [hidden email] ; https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.fantomas.sk%2F&amp;data=04%7C01%7Ccarlos.onrubia.aviles%40proximus.com%7Ce40888443de343c66a9408d8d3218eb1%7Ce7ab81b21e844bf79dcbb6fec01ed138%7C0%7C0%7C637491488366965000%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=KzvQWs%2BuNEwQvNH2rKKOreQlm2YhJfYYPrssbqswhV4%3D&amp;reserved=0
Warning: I wish NOT to receive e-mail advertising to this address.
Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
Linux IS user friendly, it's just selective who its friends are...
_______________________________________________
Please visit https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.isc.org%2Fmailman%2Flistinfo%2Fbind-users&amp;data=04%7C01%7Ccarlos.onrubia.aviles%40proximus.com%7Ce40888443de343c66a9408d8d3218eb1%7Ce7ab81b21e844bf79dcbb6fec01ed138%7C0%7C0%7C637491488366965000%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=glCh5z35uLUmPPW86kRaScRn4ZhytXWLO4BewiR3H7Q%3D&amp;reserved=0 to unsubscribe from this list

ISC funds the development of this software with paid support subscriptions. Contact us at https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.isc.org%2Fcontact%2F&amp;data=04%7C01%7Ccarlos.onrubia.aviles%40proximus.com%7Ce40888443de343c66a9408d8d3218eb1%7Ce7ab81b21e844bf79dcbb6fec01ed138%7C0%7C0%7C637491488366969979%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=qQ7VCy6Gav8js8yeMQVEL1XgzW4hAscFrulvYjfK8Gc%3D&amp;reserved=0 for more information.


bind-users mailing list
[hidden email]
https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.isc.org%2Fmailman%2Flistinfo%2Fbind-users&amp;data=04%7C01%7Ccarlos.onrubia.aviles%40proximus.com%7Ce40888443de343c66a9408d8d3218eb1%7Ce7ab81b21e844bf79dcbb6fec01ed138%7C0%7C0%7C637491488366969979%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=cV83jmF%2BfQ2vNyNhHvV9%2F%2Ff8GX6FS63712vB7M3X2bA%3D&amp;reserved=0
This e-mail cannot be used for other purposes than Proximus business use. See more on https://www.proximus.be/maildisclaimer
_______________________________________________
Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list

ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.


bind-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/bind-users
Reply | Threaded
Open this post in threaded view
|

Re: underscore in A or PTR records

Reindl Harald
In reply to this post by ONRUBIA AVILES Carlos (CCS/MST)


Am 17.02.21 um 09:50 schrieb ONRUBIA AVILES Carlos (CCS/MST):
> Hello,
>
> Thanks for these clarifications.
> The issue we face is that a telecom provider ask us to implement a PTR record with a name like "example_try.net"

point out to that provider it's a bad idea and that they should know that!

i can't count how often developers wasted hours because they used a _ in
the hostname and MSIE had strange cookie behavior with the illegal
hostname at the final tests after development web applications on Firefox
_______________________________________________
Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list

ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.


bind-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/bind-users
Reply | Threaded
Open this post in threaded view
|

Re: underscore in A or PTR records

Reindl Harald
In reply to this post by ONRUBIA AVILES Carlos (CCS/MST)


Am 17.02.21 um 10:41 schrieb ONRUBIA AVILES Carlos (CCS/MST):
> 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" ?

_ is not allowed in hostnames

> 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

_ is not allowed in hostnames


https://tools.ietf.org/html/rfc1123
2.1  Host Names and Numbers

The syntax of a legal Internet host name was specified in RFC-952
[DNS:4].  One aspect of host name syntax is hereby changed: the
restriction on the first character is relaxed to allow either a letter
or a digit.  Host software MUST support this more liberal syntax.

1. A "name" (Net, Host, Gateway, or Domain name) is a text string up to
24 characters drawn from the alphabet (A-Z), digits (0-9), minus sign
(-), and period (.)
_______________________________________________
Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list

ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.


bind-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/bind-users
Reply | Threaded
Open this post in threaded view
|

Re: underscore in A or PTR records

Matus UHLAR - fantomas
In reply to this post by ONRUBIA AVILES Carlos (CCS/MST)
On 17.02.21 09:41, ONRUBIA AVILES Carlos (CCS/MST) wrote:
>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" ?

substitute the last word with "hostnames" (a mistype).

I mean that since rfc1123 prohibits using underscores in hostnames, you
should not try to use them in hostnames.

Othersise, you may expect different problems on different places, and
whenever you'll solve such problem, people can tell you it's your problem.

>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.

yes, exactly.

>Sensitivity: Internal Use Only

this is really useless here, since you posted this to public mailing list.


--
Matus UHLAR - fantomas, [hidden email] ; http://www.fantomas.sk/
Warning: I wish NOT to receive e-mail advertising to this address.
Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
Remember half the people you know are below average.
_______________________________________________
Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list

ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.


bind-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/bind-users
Reply | Threaded
Open this post in threaded view
|

Re: underscore in A or PTR records

Ondřej Surý
In reply to this post by ONRUBIA AVILES Carlos (CCS/MST)
>
> On 17. 2. 2021, at 9:50, ONRUBIA AVILES Carlos (CCS/MST) <[hidden email]> wrote:
>
> The issue we face is that a telecom provider ask us to implement a PTR record with a name like “example_try.net"

You are mixing the two things here. If the provider has asked you to create a PTR record,
why do you keep trying to create a forward record? There’s some information missing somewhere.

Ondrej
--
Ondřej Surý (He/Him)
[hidden email]


_______________________________________________
Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list

ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.


bind-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/bind-users

signature.asc (849 bytes) Download Attachment
Reply | Threaded
Open this post in threaded view
|

RE: underscore in A or PTR records

ONRUBIA AVILES Carlos (CCS/MST)
Hello,

Indeed my question was on A record but the issue is on PTR record.
I can configure the following line:

_ptr.dekil.nl.      3600    IN      PTR     _81.99-129-109.adsl-dyn.isp.dekil.nl

It works....we can use "_"  in both sides.


But what is strange is that the following configuration do not work:

9.10.238.195.in-addr.arpa.       3600    IN      PTR     por_tal-bis.skynet.be.

"_" is not allowed

Is it due to extra check by bind when it sees it is an arpa zone so no  "_" is allowed?


Regards,

Carlos,


Sensitivity: Internal Use Only

-----Original Message-----
From: Ondřej Surý <[hidden email]>
Sent: 17 February 2021 10:52
To: ONRUBIA AVILES Carlos (CCS/MST) <[hidden email]>
Cc: Mark Andrews <[hidden email]>; [hidden email]
Subject: Re: underscore in A or PTR records

>
> On 17. 2. 2021, at 9:50, ONRUBIA AVILES Carlos (CCS/MST) <[hidden email]> wrote:
>
> The issue we face is that a telecom provider ask us to implement a PTR record with a name like “example_try.net"

You are mixing the two things here. If the provider has asked you to create a PTR record, why do you keep trying to create a forward record? There’s some information missing somewhere.

Ondrej
--
Ondřej Surý (He/Him)
[hidden email]
This e-mail cannot be used for other purposes than Proximus business use. See more on https://www.proximus.be/maildisclaimer
_______________________________________________
Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list

ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.


bind-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/bind-users
Reply | Threaded
Open this post in threaded view
|

Re: underscore in A or PTR records

Sten Carlsen


> On 17 Feb 2021, at 12.34, ONRUBIA AVILES Carlos (CCS/MST) <[hidden email]> wrote:
>
> Hello,
>
> Indeed my question was on A record but the issue is on PTR record.
> I can configure the following line:
>
> _ptr.dekil.nl.      3600    IN      PTR     _81.99-129-109.adsl-dyn.isp.dekil.nl
>
> It works....we can use "_"  in both sides.
>
>
> But what is strange is that the following configuration do not work:
>
> 9.10.238.195.in-addr.arpa.       3600    IN      PTR     por_tal-bis.skynet.be.
>
> "_" is not allowed
>
> Is it due to extra check by bind when it sees it is an arpa zone so no  "_" is allowed?

As previously mentioned, the RFCs expressly forbids the "_" in names.

I assume that a leading "_" slips past Bind's control because it "could" be part of a valid but at compile time unknown _tcp -like label.

>
>
> Regards,
>
> Carlos,
>
>
> Sensitivity: Internal Use Only
>
> -----Original Message-----
> From: Ondřej Surý <[hidden email]>
> Sent: 17 February 2021 10:52
> To: ONRUBIA AVILES Carlos (CCS/MST) <[hidden email]>
> Cc: Mark Andrews <[hidden email]>; [hidden email]
> Subject: Re: underscore in A or PTR records
>
>>
>> On 17. 2. 2021, at 9:50, ONRUBIA AVILES Carlos (CCS/MST) <[hidden email]> wrote:
>>
>> The issue we face is that a telecom provider ask us to implement a PTR record with a name like “example_try.net"
>
> You are mixing the two things here. If the provider has asked you to create a PTR record, why do you keep trying to create a forward record? There’s some information missing somewhere.
>
> Ondrej
> --
> Ondřej Surý (He/Him)
> [hidden email]
> This e-mail cannot be used for other purposes than Proximus business use. See more on https://www.proximus.be/maildisclaimer
> _______________________________________________
> Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list
>
> ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.
>
>
> bind-users mailing list
> [hidden email]
> https://lists.isc.org/mailman/listinfo/bind-users

_______________________________________________
Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list

ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.


bind-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/bind-users
Reply | Threaded
Open this post in threaded view
|

Re: underscore in A or PTR records

Mark Andrews
No. The PTR records that map from IP address to hostname enforce the hostname rules.

--
Mark Andrews

> On 18 Feb 2021, at 02:20, Sten Carlsen <[hidden email]> wrote:
>
> 
>
>> On 17 Feb 2021, at 12.34, ONRUBIA AVILES Carlos (CCS/MST) <[hidden email]> wrote:
>>
>> Hello,
>>
>> Indeed my question was on A record but the issue is on PTR record.
>> I can configure the following line:
>>
>> _ptr.dekil.nl.      3600    IN      PTR     _81.99-129-109.adsl-dyn.isp.dekil.nl
>>
>> It works....we can use "_"  in both sides.
>>
>>
>> But what is strange is that the following configuration do not work:
>>
>> 9.10.238.195.in-addr.arpa.       3600    IN      PTR     por_tal-bis.skynet.be.
>>
>> "_" is not allowed
>>
>> Is it due to extra check by bind when it sees it is an arpa zone so no  "_" is allowed?
>
> As previously mentioned, the RFCs expressly forbids the "_" in names.
>
> I assume that a leading "_" slips past Bind's control because it "could" be part of a valid but at compile time unknown _tcp -like label.
>
>>
>>
>> Regards,
>>
>> Carlos,
>>
>>
>> Sensitivity: Internal Use Only
>>
>> -----Original Message-----
>> From: Ondřej Surý <[hidden email]>
>> Sent: 17 February 2021 10:52
>> To: ONRUBIA AVILES Carlos (CCS/MST) <[hidden email]>
>> Cc: Mark Andrews <[hidden email]>; [hidden email]
>> Subject: Re: underscore in A or PTR records
>>
>>>
>>>> On 17. 2. 2021, at 9:50, ONRUBIA AVILES Carlos (CCS/MST) <[hidden email]> wrote:
>>>
>>> The issue we face is that a telecom provider ask us to implement a PTR record with a name like “example_try.net"
>>
>> You are mixing the two things here. If the provider has asked you to create a PTR record, why do you keep trying to create a forward record? There’s some information missing somewhere.
>>
>> Ondrej
>> --
>> Ondřej Surý (He/Him)
>> [hidden email]
>> This e-mail cannot be used for other purposes than Proximus business use. See more on https://www.proximus.be/maildisclaimer
>> _______________________________________________
>> Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list
>>
>> ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.
>>
>>
>> bind-users mailing list
>> [hidden email]
>> https://lists.isc.org/mailman/listinfo/bind-users
>
> _______________________________________________
> Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list
>
> ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.
>
>
> bind-users mailing list
> [hidden email]
> https://lists.isc.org/mailman/listinfo/bind-users

_______________________________________________
Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list

ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.


bind-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/bind-users