Subject: Re: Allowing IP addresses as path-identiites

From: John Stanley <[email-masked]>
Date: Tue, 6 Sep 2005 08:18:52 -0700 (PDT)

Harald Tveit Alvestrand <harald@xxxxxxxxxxxxx>:

>YES - IP addresses should be allowed as path-identity.

Since you aren't going to stop it, it's better to figure out how to allow 
it and have it coexist peacefully.

>NOTE: If we disallow IP addresses as path-identities, we will still allow 
>them as "diagnostic data" -

I'm sorry, but I see no "diagnostic data" component in the definition of 
the path header. I see "path-identity", I see "path-keyword", and I see 
"path-delimiter." If we disallow IP addresses as path-identities, then 
they are disallowed altogether, since they fit neither the limited 
definition of path-keyword nor path-delimiter.

>I think we should delete option 2 in the list below.

There is no reason to, if you encode the IPv6 addresses as has been 
suggested several times. The only reason not to allow IPv6 is the 
dead:beef problem, which is trivially avoided. I know of no reason not to 
allow IPv4. It is, for routable addresses, as unique as the FQDN.

---

From: John Stanley <[email-masked]>
Date: Wed, 7 Sep 2005 09:42:45 -0700 (PDT)

"Forrest J. Cavalier III" <forrest@xxxxxxxxxxxxxxx>:

> So where do IP addresses for diagnostics fit in?

Not in the path header field, since that is composed of path-identities.
Either it is a path-identity, a path-delimiter, or a keyword.

>but impossible to determine if something is a server identity or a 
>diagnostic when parsing.

Since we have no definition of "diagnostic", yep, anything that appears in 
the path header that isn't a delimiter or keyword is a path-identity.

"Charles Lindsey" <chl@xxxxxxxxxxxxxxxx>:

>But you don't actually gain anything by forbidding them. The dead:beef
>problem still remains (because IP addresses are still allowed as
>diagnostics) and the syntax becomes a little more complicated.

1. the "dead:beef" problem is trivially solved and said solution has been 
on the table for probably more than a month now. The only reason I've seen 
to disallow IPv6 is that problem; it's been solved, so can we move on yet?

2. If you disallow IP addresses as path-identities, they are disallowed in
the Path header field, since IP addresses are not delimiters and are not
keywords. You cannot say "disallow as path-identity" and then claim they
are still allowed. That's a contradiction. Oh, of course, you could create
a "Diagnotic-Thing"  header field and put them there, but the question is
about path-identities, and those are what appears in path header fields.

---

From: Harald Tveit Alvestrand <[email-masked]>
Date: Thu, 08 Sep 2005 08:28:31 +0200

Forrest,

why do you bother responding to this thread when you can't be bothered to 
read the message that started it?

--On 7. september 2005 09:15 -0400 "Forrest J. Cavalier III" 
<[email-masked]> wrote:

> Does that mean that someone saying NO for path-identity is also
> saying that they reject uses of IP for diagnostics in path-list, since
> the grammar says a path-list contains path-identities, not server-names?

That message specifically said:

> them as "diagnostic data" - nobody's proposed that we should declare
> articles that have IP addresses in the path as non-conformant. However,
> if we disallow them, they WILL be disallowed in Injection-info and Xref,
> which are the two other places that use them.