Scanning Linux Port by nc Command

If you need to find out which ports are opened on linux/unix server, try nc Command:

$ nc -z localhost 1-1023

Connection to localhost 25 port [tcp/smtp] succeeded!
Connection to localhost 80 port [tcp/http] succeeded!
Connection to localhost 143 port [tcp/imap] succeeded!
Connection to localhost 199 port [tcp/smux] succeeded!
Connection to localhost 783 port [tcp/*] succeeded!
Connection to localhost904 port [tcp/vmware-authd] succeeded!
Connection to localhost 993 port [tcp/imaps] succeeded!