I thought the 600 ports were for rsh, but by they alternate between TCP and UDP, and aren't contiguous, I don't know.
TCP port 514 is for "rsh":
port tcp udp
...
514 shell syslog
The 600 ports you see are probably for ONC RPC services other than the one officially assigned a port because ONC doesn't work if you don't give it a well-known port (i.e., portmapper/rpcbind, port 111) and the one that could, in theory, use any port, but always gets a fixed port in practice and the spec for version 3 of which says "use port 2049" (NFS).
Try "rpcinfo -p" against the server, to see what ports various ONC RPC services were assigned. No guarantees that a given service will get the same port every time it's started.