How To Install and Configure Ubuntu Firewall

Contents

Overview ....................................................................................................................................................... 2

Applies To ...................................................................................................................................................... 2

Install ufw Package........................................................................................................................................ 2

Allow incoming SSH Connections.................................................................................................................. 3

Allow incoming TCP and UDP Connections ................................................................................................... 3

Allow incoming Connections by Port & Protocol type .................................................................................. 3

Allow incoming Connections by Service Name ............................................................................................. 3

Allow Incoming connection by Port Ranges & Protocol Type....................................................................... 3

tcp connections ..................................................................................................................................... 3

udp connections .................................................................................................................................... 3

Allow Incoming connection by IP Address .................................................................................................... 3

Deny incoming Connections ......................................................................................................................... 3

Validate Rule deletion ................................................................................................................................... 4

Deleting Firewall Rules .................................................................................................................................. 4

Enable or Disable Firewall Service – System Startup .................................................................................... 5

Enabling at OS Startup .............................................................................................................................. 5

Disabling at OS Startup ............................................................................................................................. 5

Reset to Default state ................................................................................................................................... 5

sudo ufw reset .............................................................................................................................................. 5

How To Install and Configure Ubuntu Firewall

Overview

Firewall plays an important role in providing security to the host, by blocking traffic from unwanted

sources.

Applies To

Ubuntu 12.04

Install ufw Package

sudo aptitude -y install ufw

or

sudo apt -y install ufw

Note: "-y" switch will not ask for confirmation before download and installation.

Check the Firewall Status

sudo ufw status

or

sudo ufw status verbose

Note: "verbose" will give verbose output

Output:

Status: active

Logging: on (low)

Default: deny (incoming), allow (outgoing)

New profiles: skip

To Action From

-- ------ ----

22 ALLOW Anywhere

22 ALLOW Anywhere (v6)

How To Install and Configure Ubuntu Firewall

Allow incoming SSH Connections

In order to allow ssh connection on the host, open the port “22” alternatively you could open by specifying

the service name “ssh”

sudo ufw allow ssh

Output:

Rule added

Rule added (v6)

Allow incoming TCP and UDP Connections

Allowing ping requests, execute the command

sudo ufw allow 8/tcp

sudo ufw allow 8/udp

Allow incoming Connections by Port & Protocol type

sudo ufw allow 22/tcp

Allow incoming Connections by Service Name

sudo ufw allow www

Allow Incoming connection by Port Ranges & Protocol Type

For tcp connections

sudo ufw allow 3000:3500/tcp

For udp connections

sudo ufw allow 3000:3500/udp

Allow Incoming connection by IP Address

sudo ufw allow from 192.168.1.25

Deny incoming Connections by port & Protocol Type

sudo ufw deny 80/tcp

Output:

Rule added

Rule added (v6)

How To Install and Configure Ubuntu Firewall

Validate Rule deletion

sudo ufw status verbose

Status: active

Logging: on (low)

Default: deny (incoming), allow (outgoing)

New profiles: skip

To Action From

-- ------ ----

22 ALLOW IN Anywhere

Anywhere ALLOW IN 192.168.255.255

80/tcp DENY IN Anywhere

22 ALLOW IN Anywhere (v6)

80/tcp DENY IN Anywhere (v6)

Deleting Firewall Rules

sudo ufw delete allow from 192.168.255.255

Output:

Rule deleted

sudo ufw status verbose

Status: active

Logging: on (low)

Default: deny (incoming), allow (outgoing)

New profiles: skip

To Action From

-- ------ ----

22 ALLOW IN Anywhere

80/tcp DENY IN Anywhere

22 ALLOW IN Anywhere (v6)

80/tcp DENY IN Anywhere (v6)

How To Install and Configure Ubuntu Firewall

Enable or Disable Firewall Service – System Startup

Enabling at OS Startup

sudo ufw enable

Output:

Command may disrupt existing ssh connections. Proceed with operation (y|n)? y

Firewall is active and enabled on system startup

Disabling at OS Startup

sudo ufw disable

Output:

Firewall stopped and disabled on system startup

Reset to Default state

sudo ufw reset

Output:

Resetting all rules to installed defaults. This may disrupt existing ssh

connections. Proceed with operation (y|n)? y

Backing up 'user.rules' to '/lib/ufw/user.rules.20140220_105532'

Backing up 'after6.rules' to '/etc/ufw/after6.rules.20140220_105532'

Backing up 'user6.rules' to '/lib/ufw/user6.rules.20140220_105532'

Backing up 'before6.rules' to '/etc/ufw/before6.rules.20140220_105532'

Backing up 'after.rules' to '/etc/ufw/after.rules.20140220_105532'

Backing up 'before.rules' to '/etc/ufw/before.rules.20140220_105532'