Guy Harris wrote:
On Dec 15, 2010, at 8:26 PM, Chris Maynard wrote:
Guy Harris <guy@...> writes:
SHOULD in some RFC - or even a MUST - but I don't know offhand what
RFC that is)
http://tools.ietf.org/html/rfc2119
Sorry, I didn't make it clear that "what RFC that is" is "what RFC - if
any - says that ephemeral ports should be handed out by default", not
"what RFC explains what SHOULD and MUST mean". *Is* there an RFC that
describes well-known, registered, and ephemeral ports? The first two of
them are mentioned in the IANA port number assignment list:
http://www.iana.org/assignments/port-numbers
but that doesn't mention ephemeral ports.
There's been a lot of discussion about port assignment/registration on
the IETF tsvwg mailing list of late. There's a draft floating around
which describes the port number ranges in section 6:
http://tools.ietf.org/html/draft-ietf-tsvwg-iana-ports-09#section-6
and then goes on to say, in section 8.1.1:
o Ports in the Dynamic Ports range (49152-65535) have been
specifically set aside for local and dynamic use and cannot be
assigned through IANA. Application software may simply use any
dynamic port that is available on the local host, without any sort
of assignment. On the other hand, application software MUST NOT
assume that a specific port number in the Dynamic Ports range will
always be available for communication at all times, and a port
number in that range hence MUST NOT be used as a service
identifier.