What methods can be used to check if the required port is open on a Linux server?

There are several ways to check if a specific port is open on a Linux server:

• netstat

netstat -tuln | grep <port>

Shows which ports are listening for processes.

• ss (modern alternative to netstat)

ss -tuln | grep <port>

• telnet

telnet <server_address> <port>

If the connection is established, the port is open.

• nc (netcat)

nc -zv <server_address> <port>

Checks the availability of the port.

• nmap

nmap -p <port> <server_address>

Scans the port and shows its status.

The choice of method depends on the installed utilities and the task.