Re: TCPMUX (RFC 1078) status

[Wesley Eddy <[e-mail]>]

On 8/15/2013 4:18 PM, Joe Touch wrote:
> 
> 
> On 8/10/2013 12:29 PM, Wesley Eddy wrote:
>> On 8/10/2013 1:43 AM, Martin Sustrik wrote:
>>> Hi all,
>>>
>>> Does anyone have any idea how widely is TCPMUX (RFC 1078) protocol used?
>>> Is it the case that there are inetd daemons in TCPMUX mode running
>>> everywhere, or can it be rather considered a dead protocol?
>>>
>>> Specifically, if I implement a new TCPMUX daemon how likely I am to
>>> clash with an existing TCPMUX daemon listening on port 1?
>>>
>>
>>
>> It's in the FreeBSD inetd, among others, but to to my
>> knowledge, nobody actually turns it on.  There are
>> probably security issues.
> 
> There are semantics issues to; see draft-touch-tcp-portnames-00 for
> information (this is being revised for resubmission shortly, FWIW).
> 


I totally agree.  In fact, in the update to the TCP roadmap [1], we
added TCPMUX to the section on "Historic and Undeployed Extensions",
though it definitely bears further discussion than is currently in
the roadmap.  I think we should add a reference to your portnames doc
to explain why this should be Historic plus check a bit more to see if
the code that's out there is really being used or whether it's just
hanging out like a vestigal limb in the various inetd packages.

If it's fair to ask Martin ... I'm kind of curious why you might want
to be using it or think it sounds useful?  I think a lot of admins
would be concerned that it could be used to get around port-based
firewall rules, etc.

[1] http://tools.ietf.org/html/draft-ietf-tcpm-tcp-rfc4614bis-00

-- 
Wes Eddy
MTI Systems