How to manage Ubuntu firewall using UFW commands
How to manage Ubuntu firewall using UFW commands
The UFW or Uncomplicated Firewall is an application to manage an iptables based firewall on Ubuntu. UFW is the default firewall configuration tool for Ubuntu Linux and provides a user-friendly way to configure the firewall, the UFW command is just like English language so the commands are easy to remember. The UFW firewall supports both IPv4 and IPv6. This tutorial explains the management of Ubuntu firewall using UFW commands.
Pre-Requisites
- Ubuntu
- Root privileges or admin privileges
UFW Commands
To enable UFW in the terminal, execute the following command.
root@linuxhelp:~# ufw enable
Firewall is active and enabled on system startup
To know about the firewall status, run the following command.
root@linuxhelp:~# ufw status
Status: active
The UFW also helps us to open a particular port to allow the access to a user and trigger the following command.
root@linuxhelp:~# ufw allow 22 Rule added Rule added (v6) root@linuxhelp:~# ufw status Status: active To Action From -- ------ ---- 22 ALLOW Anywhere 22 (v6) ALLOW Anywhere (v6)
We can also add a rule by using the insert command and display the status in numbered format by running the following command.
root@linuxhelp:~# ufw insert 1 allow 80 Rule inserted Rule inserted (v6) root@linuxhelp:~# ufw status numbered Status: active To Action From -- ------ ---- [ 1] 80 ALLOW IN Anywhere [ 2] 22 ALLOW IN Anywhere [ 3] 80 (v6) ALLOW IN Anywhere (v6) [ 4] 22 (v6) ALLOW IN Anywhere (v6)
To deny a connection from a open port, run the following command.
root@linuxhelp:~# ufw deny 25 Rule added Rule added (v6) root@linuxhelp:~# ufw status Status: active To Action From -- ------ ---- 80 ALLOW Anywhere 25 DENY Anywhere 25 (v6) DENY Anywhere (v6)
To remove a rule, use the delete command to delete a specific rule.
root@linuxhelp:~# ufw delete deny 25 Rule deleted Rule deleted (v6) root@linuxhelp:~# ufw status Status: active To Action From -- ------ ---- 22 ALLOW Anywhere 22 (v6) ALLOW Anywhere (v6) root@linuxhelp:~# ufw status numbered Status: active To Action From -- ------ ---- [ 1] 80 ALLOW IN Anywhere [ 2] 22 ALLOW IN Anywhere [ 3] Anywhere ALLOW IN 15.15.15.51 [ 4] 22 ALLOW IN 15.15.15.51 root@linuxhelp:~# ufw delete 3 Deleting: allow 80 Proceed with operation (y|n)? y Rule deleted (v6) root@linuxhelp:~# ufw status numbered Status: active To Action From -- ------ ---- [ 1] 80 ALLOW IN Anywhere [ 2] 22 ALLOW IN Anywhere [ 3] 22 ALLOW IN 15.15.15.51
To allow connections from a specific IP address, use the following command.
root@linuxhelp:~# ufw allow from 15.15.15.51 Rule added root@linuxhelp:~# ufw status Status: active To Action From -- ------ ---- Anywhere ALLOW 15.15.15.51
We can also specify a specific port for the IP address that is allowed to connect by adding " to any port" followed by the port number.
root@linuxhelp:~# ufw allow from 15.15.15.51 to any port 22 Rule added root@linuxhelp:~# ufw status Status: active To Action From -- ------ ---- Anywhere ALLOW 15.15.15.51 22 ALLOW 15.15.15.51
To allow a subnet of IP addresses, use a CIDR notation to specify a netmask as the command below.
root@linuxhelp:~# ufw allow from 15.15.15.0/24 Rule added root@linuxhelp:~# ufw status Status: active To Action From -- ------ ---- Anywhere ALLOW 15.15.15.51 22 ALLOW 15.15.15.51 Anywhere ALLOW 15.15.15.0/24
This command is executed to view the list of applications that is installed in the system.
root@linuxhelp:~# ufw app list
Available applications:
Apache
Apache Full
Apache Secure
CUPS
Samba
To allow traffic to a port using an application profile run the following command.
root@linuxhelp:~# ufw allow samba Rule added Rule added (v6) root@linuxhelp:~# ufw allow from 192.168.0.0/24 to any app Samba Rule added root@linuxhelp:~# ufw status Status: active To Action From -- ------ ---- 80 ALLOW Anywhere Samba ALLOW Anywhere Samba ALLOW 192.168.0.0/24
To view details about particular application information such as ports, protocols, etc., that are defined for an application, enter the following command.
root@linuxhelp:~# ufw app info Samba
Profile: Samba
Title: LanManager-like file and printer server for Unix
Description: The Samba software suite is a collection of programs that
implements the SMB/CIFS protocol for unix systems, allowing you to serve
files and printers to Windows, NT, OS/2 and DOS clients. This protocol is
sometimes also referred to as the LanManager or NetBIOS protocol.
Ports:
137,138/udp
139,445/tcp
The list of commands to be used in UFW command is done as shown above.
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