How to Check FTP Port 21 Is Not Blocked

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March 20, 2017

1 min read

Checking port 21 whether it is blocked or not, can be through the terminal or command prompt. Port 21 is generally made for FTP (File Transfer Protocol) connections, this port is used by FTP clients to connect to the FTP server when the user will access the FTP server. So if you have problem connecting FTP client to your FTP account, this is a great way to check if port 21 is blocked or not.

Read also: How to Check SMTP Port 587 is Not Blocked

What Do You Need to Check FTP Ports?

Before moving on to the next step, make sure that you can access the Command Prompt (Windows), Terminal (Linux), or MacOS Terminal.

Step 1: Open Command Prompt/Terminal on Your Computer

There are slight differences in this first step, depending on the operating system you are using. If you are using Windows, you can use the Command Prompt. Meanwhile, you can use Terminal for both Linux and MacOS operating systems. Here we present the method for you.


First of all, please press the button Windows + R on your keyboard to display functions Run. After that you will see a screen like below.

run on windows

type cmd in the available fields, then press the button OK.

You will see the Command Prompt display in black.

windows command prompt

To check if port 21 is open, telnet on Windows needs to be enabled first. If telnet is not active, you will get a message like below.

style="padding-left: 30px;">'telnet' is not recognized as an internal or external command, operable program or batch file.

If you see a message like the one above, please enable telnet first. You can follow the steps below.

1. Click button Start on Windows or press the key Windows on your keyboard.

2. Type “Turn Windows features on and off“then press ENTER.

3. After that, search Telnet Client, put a check mark, then press the button OKas seen in the image below.

activate telnet


To open Terminal on Linux, please press button Ctrl+alt+T simultaneously. Next you will see a black screen console as shown below.

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Also Read: Easy Ways to Create an FTP Server


Meanwhile, to open Terminal on MacOS, please first open the MacOS Launchpad by pressing the button F4.

After that please search by typing “terminal” without quotes and press ENTER.

mac terminal

Step 2: Use Telnet to Check Port 21 Not Blocked

After the Command Prompt / Terminal console opens, please type the code below. Enter your website’s domain name instead

telnet 21

check port 21

If it is successful, you will see a message as seen below.

220---------- Welcome to Pure-FTPd [privsep] [TLS] ----------
220-You are user number 8 of 100 allowed.
220-Local time is now 09:57. Server port: 21.
220-This is a private system - No anonymous login
220-IPv6 connections are also welcome on this server.
220 You will be disconnected after 3 minutes of inactivity.

loading="lazy" class="aligncenter wp-image-2965" title="ftp port" src="" alt="port 21" width="650" height="204" srcset=" 663w, 300w, 500w, 400w, 200w, 50w" sizes="(max-width: 650px) 100vw, 650px"/>

If you don’t see the message, it means Port 21 is blocked.


In this tutorial you have learned how to use telnet to check if the default FTP port 21 is open. If the results of the check show that the port is closed, the best thing you can do is to contact your service provider and request that this port be opened. Closing Port 21 means you cannot use FTP hosts on the network.

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