mike,
the "reserved" ports are *server-side* ports that were reserved via IANA by users/vendors who want to avoid port collisions with others.
for example,
veritas-vis1 2993/tcp VERITAS VIS1 veritas-vis1 2993/udp VERITAS VIS1 veritas-vis2 2994/tcp VERITAS VIS2 veritas-vis2 2994/udp VERITAS VIS2 # Dinkar Chivaluri dinkar <at symbol> veritas.com
in this case a gentleman at Veritas has formally (via IANA) reserved these ports for Veritas use in their applications. of course other vendor's clients might connect to this port, but no other server software should utilize this range of host ports.
as for accepting connections from various ports, well there is little control nor written documentation governing what ports the client should use when initiating a connection. historically, clients would be expected to use ports above 1024, however with the introduction of operating systems that were, let's just say, "adventurous" in their interpretation of the various networking RFC's and "standards", well any expectation of conformity is now very gone.
summary: if you are developing server software and want to reserve a port or port range for your use, contact IANA. if you are running a server, you should expect client connections from any port.
hope that helps. jim
Michael T. Davis wrote:
This is a general port usage query, rather than IPF specific, so if it's too OT, I apologize.
According to...
http://www.iana.org/assignments/port-numbers
...port 1024 (among others) is (are) IANA reserved. Does this mean that this (these) port(s) must not be used, shouldn't be used, or what? Say you have a Web server running on port 80, as usual. Should a connection to that Web server from another machine that uses port 1024 be allowed? What about data from any random port on another machine to a service running on port 1024? If someone could point me at a specific reference as to just what "reserved" means in this context, I'd appreciate it.
Thanks, Mike -- Michael T. Davis | Systems Specialist: ChE,MSE E-mail: [EMAIL PROTECTED] | Departmental Networking/Computing -or- [EMAIL PROTECTED] | The Ohio State University http://www.er6.eng.ohio-state.edu/~davism/ | 197 Watts, (614) 292-6928
