Application background the code you compiled is named "port"_ scanning。 C“GCC port_ scanning。 C O port_ scanning。 Come out " Then we run "port."_ scanning。” File input / port_ scanning.out . 10.242.130.111 1 20000 is the key technology of port opening between IP (10.242.130.111) 1 and 20000. Socket programming under Linux adopts C language and UNIX