/The list of
UDP ports at Wikipedia(1) doesn't show port 93 or 10093, /> >/so I suggest we
correct Wikipedia's list, since port 93 is shown as /> >/assigned to
"Device Control Protocol" by the IANA(3). /
Yes, our usage of port 93/UDP
for AXUDP is completely unrecognized by
IANA. There is no official document describing AXUDP so there is no
way for us to claim a port - although there's no prohibition on
using any port number we want, since port numbers are not absolutes.
Still, it's not wise to double-up on port numbers.
In the "old days" it was quite easy to register port numbers, and in fact
I have registered a few myself that I still use for similar but not the same
purposes (459, 1535, 1536). However, it appears to be not as simple anymore
and looking at protocols that are in much more widespread use than AXUDP it
appears to be not common anymore to register ports used only by some proprietary
protocol at IANA (there are way, way more protocols in use than those with
IANA-registered port numbers).
Note that at the time I registered the above 3, IANA would not take suggestions
for the numbers to register. I claimed different numbers that were unregistered,
but they gave me those instead. Asking for port 93 to be registered is unlikely
to succeed, 10093 may be possible.
Registered port numbers are useful mainly for open protocols that are widely
implemented and that accept unsolicited incoming connections. So everyone knows
what port you have your wellknown services listening on.
There is not much that can go wrong when using a port number without registering
it, especially when the receiving application accepts data only from a
pre-configured peer. The port numbers used essentially don't matter in that
case, the only thing you need to make sure is that you don't have another
session with that same peer that would want to use the same port number.
(e.g. it would not be wise to use port 5198/5199 as these are used by Echolink,
another port usage that is not registered at IANA and is in much more widespread
use than AXUDP)
Rob
