A server administrator has deployed a new application on a Linux server (192.168.1.50) that is configured to listen for connections on TCP port 8443. Users report they cannot access the application. The administrator confirms they can successfully ping the server's IP address from their workstations. The administrator now needs to verify from another server on the same network that port 8443 is open and a service is listening, without establishing a full interactive session. Which of the following commands would be the MOST efficient for this task?
The correct command is nc -zv 192.168.1.50 8443. The nc (netcat) utility is a versatile tool for testing network connectivity. The -z flag instructs nc to scan for listening daemons without sending any data, and the -v flag provides verbose output, indicating whether the connection succeeded or failed. This combination is highly efficient for quickly checking if a port is open.
telnet 192.168.1.50 8443 can also test a port, but it is designed for interactive sessions. It is less efficient for a quick, scripted check compared to nc -z.
netstat -an | grep 8443 must be run on the server (192.168.1.50) itself to check for listening ports. The scenario specifies the test must be performed from another server.
ping -p 8443 192.168.1.50 is incorrect because the standard ping utility uses the ICMP protocol, which does not have the concept of ports. The -p flag in ping is for specifying a data pattern, not for testing a TCP/UDP port.