How Linux detects port connectivity in bulk and whether ports are open

Is there a method for batch inspection? Some. We use NC to quickly detect the openness of the port.

The use of the NC detection port

Nc-z-W 10-u%ip%%PORT%

-Z indicates detection or scanning of ports
-W indicates time-out
-U means that the UDP protocol is used, and this parameter is NULL for the TCP protocol

For example:

[@s136. ipcpu.com ~]# nc-z-W 10-u 8.8.8.8 53Connection to 8.8.8.8, Port [Udp/domain] succeeded! [@s136. ipcpu.com ~]# nc-z-W 8.8.8.8 53Connection to 8.8.8.8, Port [Tcp/domain] succeeded! [@s136. ipcpu.com ~]# Echo $?0[@s136. ipcpu.com ~]# nc-z-w 8.8.8.7 53[@s136. ipcpu.com ~]# Echo $?1

Port successfully unicom return value is 0, prompt succeeded; otherwise return 1 without prompting any data

Suppose we had such a heap of IPs and ports.

#cat ports119.181.69.96 8080119.181.118.38 8000119.181.20.18 8080119.181.69.37 8080

We can write such a script to detect whether the port is open in bulk:

Cat Tetsport   |  While read Linedo #nc-Z-  w  $linenc-Z-w $line >/dev/null 2>&1if [$?-eq 0]thenecho $line: Okel Seecho $line: Failfi Done

Well, here's how we run the results:

119.181.69.96 8080:ok119.181.118.38 8000:ok119.181.20.18 8080:fail119.181.69.37 8080:ok