Re: [port-srv-reg] "xmp" service type and the unified IANA Service Name and Port Number Registry

[Joe Touch <[e-mail]>]

On 8/23/2011 10:41 PM, Stuart Cheshire wrote:
> On 23 Aug 2011, at 19:46, Bobby Krupczak wrote:
...
>> I use the name in getservbyname()
>
> My personal view is that getservbyname() is a flawed API with very
> limited usefulness. It simply consults the local /etc/services table on
> Unix, and, in your case, should always return the fixed constant 5270.
> So calling getservbyname("xmp", "tcp") is just a less-efficient way of
> writing "htons(5270)".

Hi, Bobby,

This view is not held by all parties involved in this issue.

My view is that getservbyname provides the same level of indirection 
inside a host that SRV records provide between hosts. In specific, 
modifications of the /etc/services tables does occur and is valid. As a 
result, I would not suggest that you change to using the port number 
directly.

My position, FWIW, is that IANA assignments were the only official ones, 
and that they will take precedent - that is what I have already 
recommended to IANA. Whether the SRV name or port name is changed, there 
are changes to code required.

The goal of this exchange is to minimize the impact of resolving the 
unification of IANA port names and SRV names. My recommendation to IANA 
is that IANA assignments should take precedence if a true conflict remains.

On one final point:

> And, getting back to your "xmp" example, "xmp" isn't even in the /etc/services table on OS X
...

Stuart - perhaps you can encourage Apple to update their /etc/services 
to track the IANA list more closely. Regardless of similar flaws in 
other OSes, this list should be updated regularly.

Joe Touch
IANA Port Review Team Lead