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

[Jeffrey Hutzelman <[e-mail]>]

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 <[e-mail]> 
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 outdated.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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