How to block IP addresses via ufw

The article describes how to block specific IP addresses via ufw.

UFW (Uncomplicated Firewall) is a standard utility for configuring iptables firewall for Ubuntu Linux OS. It uses a command line interface consisting of a small number of simple commands. UFW is a convenient way to create a basic IPv4 or IPv6 firewall to protect the server.


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Blocking specific IP addresses via ufw

Syntax:

sudo ufw deny from {ip-address-here} to any 

To block or close all packages from 192.168.1.5, enter:

 sudo ufw deny from 192.168.1.5 to any 

We show the status of the firewall including the rules. To check the newly added rules, enter:

 $ sudo ufw status numbered 

or

 $ sudo ufw status 

Blocking specific IP and port numbers via ufw

Syntax:

 ufw deny from {ip-address-here} to any port {port-number-here} 

To block or close the "spammer" IP addresses 202.54.1.5 of port 80, enter:

 sudo ufw deny from 202.54.1.5 to any port 80 

Recheck with the following command:

 $ sudo ufw status numbered 

Result:

Closing certain IP, port numbers and protocols via ufw

Syntax:

 sudo ufw deny proto {tcp|udp} from {ip-address-here} to any port {port-number-here} 

For example, blocking malicious IP addresses 202.54.1.1 tcp port 22, enter:

 $ sudo ufw deny proto tcp from 202.54.1.1 to any port 22 $ sudo ufw status numbered 

Subnet lock through ufw. The syntax is the same:

 $ sudo ufw deny proto tcp from sub/net to any port 22 $ sudo ufw deny proto tcp from 202.54.1.0/24 to any port 22 

How to remove blocking and unblock IP addresses

Syntax:

 $ sudo ufw status numbered $ sudo ufw delete NUM 

To delete rule # 4, enter:

 $ sudo ufw delete 4 

Result:

  deny from 202.54.1.5 to any port 80 Proceed with operation (y|n)? y Rule deleted 

Hint: UFW NOT blocking IP address

To avoid unnecessary problems with unnecessary blocking, you need to change the / etc / ufw / before.rules file and add the section “Block an IP Address” after “# End required lines”.

 $ sudo vi /etc/ufw/before.rules 

 # End required lines 

Add your rule for block from spam or hackers:



Save and close the file. And - restart the firewall:

 $ sudo ufw reload