Transfered from LinuxConfig.org

Question:


How do I ping a specific port of a remote server? I need to find out whether the port on the remote server is open.

Answer:
ping utility does not allow you to ping specific port on you remote server. To see whether a specific port is open on a remote server you can use port-scanner such as nmap or simply try connect to a socket ( IP-addressort ) using telnet. In the example below we test whether a port number of TCP port 80 is open a host google.com:
Code:
# nmap -p 80 -sT google.com
or
Code:
# nmap -p 80 google.com
To test a UDP port 80 use:
Code:
# nmap -p 80 -sU google.com
other way to test whether a specific port is open on a remote server is to use telnet command. Below we test whether a port 443 on host google.com is open:
Code:
# telnet google.com 443 Trying 74.125.237.19... Connected to google.com. Escape character is '^]'.