Got a question about this.
Application wants to open a TCP connection to something - say http, so the
application issues the request, TCP on the application side uses some random
port number above 1023 as the source port number. The destination port is
the well know port on the distant end.
However, I see from the IANA port listings
(http://www.isi.edu/in-notes/iana/assignments/port-numbers ) that there are
any number of registered ports above 1023. For example L2TP uses port 1701,
Groupwise uses port 1677, ands WINS uses port 1512. The IANA page itself
calls ports 1024 through 49151 "registered" and further states that only
ports 49152 and beyond are "dynamic and / or private"
Anyone ever sniffed outbound traffic and seen apps using source ports in the
1024 through 49151 range?
It just occurs to me that this has the potential of creating problems, if an
application uses a port reserved for some other application. Since most of
the ports in this "registered" range appear to be for obscure kinds of
services or applications, perhaps this isn't really and issue.
Comments?
Chuck
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