How to ping and test for a specific port from Linux or Unix command line

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I wanted to see if a specific port of a desktop computer or server is open from a Linux or Unix command line shell. How do I ping a specific port? Is it possible possible to ping an or ports?

You use the ping command to send ICMP ECHO_REQUEST packets to network computers, routers, switches and more. ping works with both IPv4 and IPv6. Ping is using ICMP protcol. The ping command can not be used to ping a specific port.
Can you ping a specific port of a server?
However, use any one of the following command to see if a port is open or not as follows:

Use telnet command

The syntax is:
telnet {host} {port}
telnet 80
telnet 80

Sample outputs:

Connected to router.
Escape character is '^]'.
telnet> q
Connection closed.

To close your session, press Ctrl+]+q.

Use nc command

The syntax is:
nc -vz {host} {port}
nc -vz 80
nc -vz 443

Sample outputs:

found 0 associations
found 1 connections:
     1:	flags=82
	outif utun1
	src port 54997
	dst port 443
	rank info not available
	TCP aux info available

Connection to port 443 [tcp/https] succeeded!

Use nmap command

The syntax is:
nmap -PNp {port} {host}
nmap -p {port} {host}
nmap -p 22
nmap -p 443

Sample outputs:

Starting Nmap 7.40 ( ) at 2017-05-24 01:00 IST
Nmap scan report for router (
Host is up (0.00034s latency).
443/tcp open  https

Nmap done: 1 IP address (1 host up) scanned in 0.04 seconds

See “Top 32 Nmap Command Examples For Sys/Network Admins” for more info.

Use bash shell

The syntax is as follows:

## check for tcp port ##
## need bash shell ##
(echo >/dev/tcp/{host}/{port}) &>/dev/null && echo "open" || echo "close"
(echo >/dev/udp/{host}/{port}) &>/dev/null && echo "open" || echo "close"
(echo >/dev/tcp/ &>/dev/null && echo "Open 22" || echo "Close 22"
(echo >/dev/tcp/ &>/dev/null && echo "Open 443" || echo "Close 443"

Sample outputs:

Close 22
Open 443

Use nping command

Nping is an open-source tool for network packet generation, response analysis and response time measurement. Nping allows users to generate network packets of a wide range of protocols, letting them tunevirtually any field of the protocol headers. While Nping can be used as a simple ping utility to detect active hosts, it can also be used as a raw packet generator. The syntax is:
sudo nping --tcp -p {port} {host}
sudo nping --tcp -p 443

Sample outputs:

Fig.01: nping just pinged host at port 443
Fig.01: nping just pinged host at port 443

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.

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5 comment

  1. The nping utility that comes with NMap allows you to ‘ping’ a port by making a TCP connection to it. This does more than just check if the port is open. It verifies that it can be connected to.

  2. The shell approach is brilliant! Especially, when you’re working with some random docker containers. Thanks a lot!

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