On Wed, Jul 22, 2020 at 01:46:38PM +0200, Ladislav Lhotka wrote:
>
>
> On 22. 07. 20 13:00, Juergen Schoenwaelder wrote:
> > Tom,
> >
> > my understanding is that Lada is now proposing something slightly
> > different but I am not sure what exactly, hence I asked again.
>
> Oh yes, I messed it up by mixing different things together, sorry. I
> checked again the ML archive, and the message that is relevant to this
> thread is this:
>
> https://mailarchive.ietf.org/arch/msg/netmod/PISOifrtow4oWLGW7meBBSri7nM/
>
> The aim of that proposal was to limit the "inet:host" type to DNS names
> that are reasonable as host names, i.e. eliminate values like "." or "_".
You are proposing to change the length restriction from 1..253 to
2..253 following RFC 952:
[...] Single character names
or nicknames are not allowed.
And you add
pattern '(.*\.)?..\-\-.*' {
modifier invert-match;
}
to restrict things to non-reserved letter-digit-hyphen labels as per
RFC 5890. Is it clear that this second restriction applies to host
names? How do you represent internationalized host names? Perhaps we
need a collection of examples? And is the pattern correct? RFC 5890
says:
Reserved LDH labels, known as "tagged domain names" in some other
contexts, have the property that they contain "--" in the third and
fourth characters but which otherwise conform to LDH label rules.
What is the '(.*\.)?' part doing in your pattern?
Finally, would it be useful to derive a host-name type from the
domain-name type (if host-names are really a strict subset of what
domain-name allows), e.g.:
typedef host-name {
type domain-name {
pattern '(.*\.)?..\-\-.*' {
modifier invert-match;
}
length "2..max";
}
description
"Host names must be at least two characters long (see RFC 952)
and they are restricted to non-reserved letter-digit-hyphen
(NR-LDH) labels (see RFC ????).";
reference
"RFC 952: DoD Internet Host Table Specification
RFC ????: ????";
}
/js
--
Juergen Schoenwaelder Jacobs University Bremen gGmbH
Phone: +49 421 200 3587 Campus Ring 1 | 28759 Bremen | Germany
Fax: +49 421 200 3103 <https://www.jacobs-university.de/>
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