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Re: Questions about draft-lear-iana-no-more-well-known-ports-00.txt

2006-05-24 16:10:02
Disclaimer - I wasn't even aware of this document before reading this thread. However, I have now read it, so feel prepared to comment.


On Wednesday, May 24, 2006 03:11:29 PM +0200 Eliot Lear <lear(_at_)cisco(_dot_)com> wrote:

Yes, the distinction between well known ports and just assigned ports is
outdated.  The overarching theme of the document is that the IANA should
be treated as a group of adults and that they should use some discretion
with oversight only where needed.

Careful here...

(1) The IANA is a group of adults, but it is no longer a group of
   protocol subject matter experts.  IMHO there is probably no need
   for IESG oversight of port number allocation, especially if we are
   eliminating the (artificial) scarcity of so-called well-known ports.

(2) As I understand it, for ports above 1024, the IANA does _not_ assign
   values - it just registers uses claimed by others.  Eliminating
   well-known ports eliminates any assignment role, and leaves us with
   just a registry of what people have claimed.  Note that this means
   there is no mechanism which prevents the same number from being
   registered by more than one registry.

That said, I support the elimination of well-known ports and transformation of the port number registry into a "flat" registry in which all ports are basically considered equal.


I do _not_ support the introduction of a charging model, for a couple of reasons. First, I don't want to see port numbers become a politicized commodity, like IP address space and domain names have.

Second, I believe that having a complete, accurate registry of port numbers is highly valuable. If there is a charge to register a port, and a recurring charge to maintain a registration, then no one will register their ports for private or vendor-specific use and/or minor protocols. That means that they won't be known to network administrators or network traffic analysis tools, and people looking for an unused port - even if they intend to register and pay for it - will have a difficult time finding one that is actually free. It also means that registrations will tend to disappear over time, such that valuable historical information is lost.

A charging model works for domain names because they have to appear in a central registry or they don't work. It works for IP addresses, mostly(*), because if two unrelated networks publish routes for the same address space, each of them loses some of the time, and no one wants to lose. It won't work for port numbers because only very widely-deployed protocols need port numbers that aren't in use by _anything_ else.


(*) Some years ago, there was a period of time lasting several months when users of a particular large network provider were unable to communicate with CMU, because that provider had usurped 128.2/16 for some private use within its network. We were Not Amused(tm), and had quite a time getting it fixed. And that was in the days when you could usually look up a network in the internic whois server, then pick up the phone and reach someone who actually understood something about his network.


-- Jeff

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