Re: [netmod] 6991bis: domain-name

[Ladislav Lhotka <[e-mail]>]

On Tue, 2019-07-23 at 00:07 +0200, Juergen Schoenwaelder wrote:
> On Mon, Jul 22, 2019 at 04:55:33PM -0400, Ladislav Lhotka wrote:
> > Juergen Schoenwaelder <[e-mail]> writes:
> > 
> > > Lada,
> > > 
> > > I do not think we can simply enlarge the value set of inet:domain-name,
> > > existing implementations using inet:domain-name may (rightfully) not
> > > expect wildcards.
> > 
> > On the other hand, the description says:
> > 
> >    It is designed to hold various types of domain names,    including
> >    names used for A or AAAA records (host names) and other    records, ...
> > 
> > So one could expect that all values that can appear e.g. in A/AAAA records
> > of DNS zone data are supported, which is not the case.
> 
> The pattern does not allow wildcards and it did so back in RFC 6021.
> We can discuss whether this is wrong but allowing wildcards or other
> new characters I think should be done with care and considering
> existing implementations.
>  
> > > What we can do is to create a new definition that has a larger value
> > > space. We can also consider to define inet:domain-name as a subset of
> > > such a larger type as long as it results in the same value space.
> > 
> > My suggestion is to remove the above sentence from the description in the
> > next revision, and leave the rest to DNS folks. There are other interesting
> > issues, such as how to model internationalized domain names.
> 
> I am not sure which problem is solved by removing the sentence.

There are many places where domain names are used. The description mentions
A/AAAA/SRV resource records even those the type is actually not well suited for
this use case.

> 
> I would perhaps understand the suggestion to _add_ an explicit
> statement right at the top that wildcards or slashes are not
> supported:
> 
> OLD:
> 
>         "The domain-name type represents a DNS domain name.  The
>          name SHOULD be fully qualified whenever possible.
> 
> NEW:
> 
>         "The domain-name type represents a DNS domain name.  The
>          name SHOULD be fully qualified whenever possible. Domain
> 	 names including wildcards or forward slashes are not
> 	 supported.

But these two unsupported cases only make sense in the context of DNS zone data.
I would suggest instead

NEW:

        "The domain-name type represents a DNS domain name.  The
         name SHOULD be fully qualified whenever possible.
         This type is not intended for modeling DNS zone data, as
         it does not support wildcards [RFC 4592] and classless
         in-addr.arpa delegations [RFC 2317]." 

Lada

> 
> This would help clarify things. People that need to represent
> wildcards etc. then know that this type is not the right one for
> them.
> 
> /js
> 
> > Lada
> > 
> > > /js
> > > 
> > > On Fri, Mar 29, 2019 at 11:20:13AM +0100, Ladislav Lhotka wrote:
> > > > Hi,  as a follow-up to my comment during the NETMOD session, I want
> > > > to propose the following update to the the inet:domain-name type.
> > > > The aim is to include use cases that are currently rejected:  -
> > > > classless in-addr.arpa delegations [RFC 2317], i.e. labels like
> > > > "128/26"  - wildcards [RFC 4592], e.g. "*.example.net"  OLD
> > > > pattern
> > > > '((([a-zA-Z0-9_]([a-zA-Z0-9\-_]){0,61})?[a-zA-Z0-9]\.)*'     +
> > > > '([a-zA-Z0-9_]([a-zA-Z0-9\-_]){0,61})?[a-zA-Z0-9]\.?)'  +     '|\.';
> > > > NEW      pattern
> > > > '((\*\.)?(([a-zA-Z0-9_]([a-zA-Z0-9\-/_]){0,61})?[a-zA-Z0-9]\.)*'
> > > > + '([a-zA-Z0-9_]([a-zA-Z0-9\-/_]){0,61})?[a-zA-Z0-9]\.?)'     +
> > > > '|\.';  Lada  --  Ladislav Lhotka Head, CZ.NIC Labs PGP Key ID:
> > > > 0xB8F92B08A9F76C67 _______________________________________________
> > > > netmod mailing list [e-mail]
> > > > https://www.ietf.org/mailman/listinfo/netmod
> > > 
> > > --  Juergen Schoenwaelder           Jacobs University Bremen gGmbH
> > > Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
> > > Fax:   [phone] <https://www.jacobs-university.de/>
> > 
> > -- 
> > Ladislav Lhotka
> > Head, CZ.NIC Labs
> > PGP Key ID: 0xB8F92B08A9F76C67
-- 
Ladislav Lhotka
Head, CZ.NIC Labs
PGP Key ID: 0xB8F92B08A9F76C67