How to List and Delete UFW Firewall Rules.

How To List And Delete UFW Firewall Rules.

In this tutorial, we will cover how to list and delete UFW firewall rules.

UFW stands for Uncomplicated Firewall, and is a user-friendly frontend for managing iptables (netfilter) firewall rules. It is the default firewall configuration tool for Ubuntu and is also available for other popular Linux distributions such as Debian and Arch Linux.

 

Listing UFW Rules

One of the most common tasks when managing a firewall is listing rules.

You can check the status of UFW and list all rules with:

sudo ufw status

If UFW is disabled you will see something like this:

Status: inactive

Otherwise, if UFW is active, the output will print a list of all active firewall rules:

Status: active

To                         Action      From
--                         ------      ----
SSH                        ALLOW       Anywhere
XX.XX.XX.XX mDNS           ALLOW       Anywhere
SSH (v6)                   ALLOW       Anywhere (v6)
ff02::fb mDNS              ALLOW       Anywhere (v6)

To get extra information use status verbose:

sudo ufw status verbose

The output will include information about the logging, default policies and new profiles:

Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing), disabled (routed)
New profiles: skip

To                         Action      From
--                         ------      ----
22/tcp (SSH)               ALLOW IN    Anywhere
XX.XX.XX.XX 5353/udp (mDNS) ALLOW IN    Anywhere
22/tcp (SSH (v6))          ALLOW IN    Anywhere (v6)
ff02::fb 5353/udp (mDNS)   ALLOW IN    Anywhere (v6)

Use status numbered to get the order and id number of all active rules. This is useful when you want to insert a new numbered rule or delete an existing rule based on its number.

sudo ufw status numbered
Status: active

     To                         Action      From
     --                         ------      ----
[ 1] 22/tcp                     ALLOW IN    Anywhere
[ 2] 22/tcp (v6)                ALLOW IN    Anywhere (v6) 

 

Deleting UFW Rules

There are two ways to delete UFW rules:

  • By rule number

  • By specification

If you are deleting firewall rules over SSH, make sure not to lock yourself out of the remote server by removing the rule that allows SSH traffic. By default, SSH listens on port 22 .

Deleting UFW rules by the rule number is easier because you only need to find and type the number of the rule you want to delete, not the complete rule.

 

Deleting UFW rules by rule number

To remove a UFW rule by its number first you need to list the rules and find the number of the rule you want to remove:

sudo ufw status numbered

The command will give you a list of all firewall rules and their numbers:

Status: active

     To                         Action      From
     --                         ------      ----
[ 1] SSH                        ALLOW IN    Anywhere
[ 2] XX.XX.XX.XX mDNS           ALLOW IN    Anywhere
[ 3] SSH (v6)                   ALLOW IN    Anywhere (v6)
[ 4] ff02::fb mDNS              ALLOW IN    Anywhere (v6)

Once you know the rule number, use the ufw delete command followed by the number of the rule you want to remove.

For example, to delete the rule with number 4, you would type:

sudo ufw delete 4

You will be prompted to confirm that you want to delete the rule:

Deleting:
 allow 22/tcp
Proceed with operation (y|n)? y

Type y, hit Enter and the rule will be deleted:

Rule deleted

Each time you remove a rule, the rules number will change. To be on the safe side, always list the rules before deleting another rule.

 

Removing UFW rules by specification

The second method to delete a rule is by using the ufw delete command followed by the rule.

For example, if you added a rule which opens the port 2222, using the following command:

sudo ufw allow 2222

You can delete the rule by typing:

sudo ufw delete allow 2222

 

Resetting UFW and removing all rules

Resetting UFW will disable the firewall, and delete all active rules. This is useful when you want to revert all of your changes and start fresh.

To reset UFW type the following command:

sudo ufw reset

 

Conclusion

You have learned how to list and delete UFW firewall rules. When configuring a firewall always allow only those incoming connections that are necessary for the proper functioning of your system.