Ports 1020-1024 purpose?

Blinker_Fluid · 11-26-2003, 05:34 PM

Got a question about ports 1020-1024 what are they used for? Most lists that show what the ports are used for show them as reserved or unknown.
Example of a port list or This one.
Got a question from someone where they are getting this error when trying to rsh to a different machine:
rshd[212310319]: connect second port 1022: Connection refused

Thanks

chort · 11-26-2003, 07:23 PM

Well 1-1023 are reserved on UNIX-like OSs for privilaged processes. 1024+ can be used by users. Also, since client connections (i.e. outbound connections or transactions) require a port, they use port numbers above 1023 (most non-UNIX-like OSs still do this even though there isn't a restriction).

rsh should be using 513 (login) and 514 (shell).

By the way, why would you use rsh? It's a very insecure login method. Use ssh instead of rsh or telnet whenever possible.

Blinker_Fluid · 12-01-2003, 10:18 AM

Quote:

Originally posted by chort
Well 1-1023 are reserved on UNIX-like OSs for privilaged processes. 1024+ can be used by users. Also, since client connections (i.e. outbound connections or transactions) require a port, they use port numbers above 1023 (most non-UNIX-like OSs still do this even though there isn't a restriction).

rsh should be using 513 (login) and 514 (shell).

By the way, why would you use rsh? It's a very insecure login method. Use ssh instead of rsh or telnet whenever possible.

It is used on a linux cluster between the host and compute nodes on the cluster's internal network.

I understood that 513 and 514 are used for rsh but does rsh open a second port to 102x? Or is the message from somewhere else?