Re: #1047 Path-identity: A proposal (perhaps)

["Charles Lindsey" <chl@xxxxxxxxxxxxxxxx>]

In <B1567455A8003F858BE0F033@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> Harald Tveit Alvestrand <harald@xxxxxxxxxxxxx> writes:

>If we explained it, would this be a reasonable text to insert in 3.1.6?
>(I've modified the BNF too. Only modified stuff included here)
>--------------------------------------------------------------------
>  A path-identity identifies an agent. For the news system to work
>  properly, the path-identity must be globally unique.
>  Traditional usage has had two means of generating unique identifiers:
>  DNS names and asserted identities. The first gets its uniqueness from
>  the DNS; the second gets its uniqueness from tradition. New servers
>  should use DNS names.

>  In some cases, one wishes to embed something into a path-entity that
>  is not a name. One common thing to embed is an IP address, serving
>  as an identity when the name of the agent is not known.

Hmmm! That looks more of a USEPRO matter. Indeed there is that and much
more in USEPRO, and I wanted it put in USEFOR, but Alexey told me it did
not belong there. So please can we be as brief as possioble in USEFOR, and
point to USEPRO for the gory details (see below)

>   path-list       =  [FWS]
>                      *( ( path-identity / path-keyword / path-address )
>                      [FWS]
>                      path-delimiter [FWS] )
>                      tail-entry [FWS]

>   path-identity   =  ( ALPHA / DIGIT )
>                      *( ALPHA / DIGIT / "-" / "." / "_" )

>   path-keyword    = "POSTED" / "MISMATCH"


>   path-address    =  IPv4address / no-fold-literal ; see [RFC2373]

A good idea, but the term <path-identity> needs to include everything that
may occur in the list, except the two keywords, because it is used with
that meaning in many places. So it would be better as:

   path-list       =  [FWS]
                      *( ( path-identity / path-keyword )
                      [FWS]
                      path-delimiter [FWS] )
                      tail-entry [FWS]

   path-identity   =  ( ALPHA / DIGIT )
                         *( ALPHA / DIGIT / "-" / "." / "_" ) /
                      IPv4address / IPv6address ; see [RFC 3986]

   path-keyword    = "POSTED" / "MISMATCH"


>  NOTE: The path-address contains characters that some systems consider
                                                       ^
                                                    legacy
>     path-delimiters. This can cause problems; path-address should
>     therefore only be used when absolutely necessary.
>     See [USEPRO] for details on when to use them.

However, that is better said in USEPRO. Moreover, it is only the ":" in an
<IPv6address> that is problematical, so that is the only case to mention
explicitly.

>--------------------------------------------------------------------

>Note that in recycling no-fold-literal, I've added [] around addresses... 
>and that a naked IPv4 address is allowed separately, because people have 
>said this is already present (too much for us to remove).

Yes, but you have also brought in a whole lot of other things, including a
further bunch of former <path-delimiter>s (even "!").

Moreover, current practice has been not to include [...] around IP
addresses when used in <path-identity>s, and "[" and "]" were also
<path-delimiter>s in the old days (though not so harmful in this
particular context). Hence I have reverted to <IPv6address> in my revised
syntax.

Here, now, is the text currently proposed for USEPRO. Maybe we should
review it now; there are several things that have come up in recent days
which maybe ought to go into it.

   News-servers need to identify themselves, by inserting their <path-
   identity>s (F-3.1.6), into Path, Injection-Info and Xref headers. An
   injecting agent MUST identify itself with the same <path-identity> in
   both Path and Injection-Info headers.  To ensure that a <path-
   identity> provides a unique identity for the news-server concerned,
   it SHOULD be one of:

   1. A fully qualified domain name (FQDN) associated with an "A" or
      "AAAA" record, which SHOULD identify the actual host inserting
      this <path-identity> and, ideally, should also be "mailable" (see
      below).

   2. A fully qualified domain name (FQDN) associated with an "MX"
      record, which MUST be "mailable".

   3. An arbitrary name believed to be unique and registered at least
      with all other news-servers receiving articles directly from the
      given one.

   4. An encoding of an IP address - <IPv4address> or <IPv6address> [RFC
      3986].

   The FQDN of a news-server is "mailable" if its administrators can be
   reached by email using both of the forms "usenet@<FQDN>" and
   "news@<FQDN>", in conformity with [RFC 2142].

   For an injecting agent prepending to a Path header (7.2.2), the
   <path-identity> MUST be option 1 or 2 and the FQDN MUST be mailable,
   and if the agent offers its services to the general public the form
   "abuse@<FQDN>" MUST also be available, unless a more specific
   complaints address has been provided in a <complainto-param> of an
   Injection-Info header (F-3.2.14).  For other agents, options 1
   through 3 are to be preferred.

>Does this make sense?

Not yet :-(

-- 
Charles H. Lindsey ---------At Home, doing my own thing------------------------
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