Code:
C:\nc>nc.exe -l -v -n -p 5555
listening on [any] 5555 ...
connect to [1ip] from (UNKNOWN) [2ip] 49183

C:\nc>nc.exe -l -v -n -p 11457
listening on [any] 11457 ...
connect to [1ip] from (UNKNOWN) [2ip] 43520

C:\nc>nc.exe -l -v -n -p 11457
listening on [any] 11457 ...
connect to [1ip] from (UNKNOWN) [2ip] 43521

C:\nc>nc.exe -l -v -n -p 4646
listening on [any] 4646 ...
connect to [1ip] from (UNKNOWN) [2ip] 41248

C:\nc>