How to set up & configure Ubuntu Firewall (UFW) for Ubuntu 18

2020-08-17 By Ryan 6451 Views linux ufw firewall security networking

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UFW is the default firewall configuration tool for Ubuntu and it was developed to ease iptables firewall configuration. It provides a user-friendly way to create an IPv4 or IPv6 host-based firewall and it is disabled by default on the ubuntu system.

Steps to install UFW

It should be installed by default in Ubuntu 18, otherwise use the command below to install.
```
# apt install ufw
```
Check the UFW status once the installation is completed.
```
# ufw status verbose
```
It is disabled by default, so use the below commands to enable and disable UFW.
```
# ufw enable

# ufw disable
```

Application Profiles

While installing any package with the apt command, it will add an application profile to /etc/ufw/applications.d directory to describe the service and contains UFW settings.

Run the below command to list all application profiles available on your server.
```
# ufw app list
```
Run the below command to find more information about a specific profile and included rules.
```
# ufw app info Apache
```
Note: Replace the Application Apache with the original Application name.

Steps to Allow Connections

Run the below command to allow the SSH connection.
```
# ufw allow ssh
```
Run the below command to allow any custom port.
```
# ufw allow 3322/tcp
```
Note: Replace the port number 3322 with your required custom port.
Run the below commands to allow HTTP - Port 80 as an example.
```
# ufw allow http

# ufw allow 80/tcp
```
Run the below commands to allow HTTPS - Port 443 as an example.
```
# ufw allow https

# ufw allow 443/tcp
```
Run the below commands to allow both TCP and UDP port ranges as an example.
```
# ufw allow 8200:8300/tcp

# ufw allow 8200:8300/udp
```
Note: Replace the port range with your required range.
Run the below commands to allow specific IP addresses and specific IP addresses on a specific port as an example.
```
# ufw allow from 123.123.123.123

# ufw allow from 123.123.123.123 to any port 22
```
Note: Replace the IP address and port with your original IP address and required port setting.

Steps to Deny Connections

Run the below command to deny all connections from an IP address.
```
# ufw deny from 123.123.123.123/24
```
Note: Replace the IP address with the original IP address.
If only need to deny access to any ports from the IP address, use the below command.
```
# ufw deny from 123.123.123.123/24 to any port 80
```
Note: Using deny rules is the same as using allow rules, here only need to replace allow with denying.

Delete UFW Rules

You can delete the UFW rules by rule number and by specifying the actual rule. Run the below commands to check the rule number and remove UFW rules.
```
# ufw status numbered

# ufw delete 5
```
Note: Replace the rule number with the original number.
Run the below command to remove the UFW rule by specifying the actual rule as an example.
```
# ufw delete allow 443/tcp
```
Note: Replace the rule allow 443/tcp with the original rule.