UncomplicatedFirewall
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| With 8.04 LTS, Ubuntu introduced the Uncomplicated Firewall (`ufw`). `ufw` is a frontend for `iptables`, and is installed but not enabled by default in Ubuntu (users must explicitly enable it). Particularly well-suited for host-based firewalls, `ufw` provides a framework for managing `netfilter`, as well as a command-line interface for manipulating the firewall. `ufw` aims to provide an easy to use interface for people unfamiliar with firewall concepts, while at the same time simplifies complicated `iptables` commands to help an adminstrator who knows what he or she is doing. `ufw` is an upstream for other distributions and graphical frontends. |
The Uncomplicated Firewall (`ufw`) is a frontend for `iptables` and is particularly well-suited for host-based firewalls. `ufw` provides a framework for managing `netfilter`, as well as a command-line interface for manipulating the firewall. `ufw` aims to provide an easy to use interface for people unfamiliar with firewall concepts, while at the same time simplifies complicated `iptables` commands to help an adminstrator who knows what he or she is doing. `ufw` is an upstream for other distributions and graphical frontends. |
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| == Basic Usage == Getting started with `ufw` is easy. For example, to enable firewall, allow ssh access, enable logging, and check the status of the firewall, perform:{{{ $ sudo ufw allow ssh/tcp $ sudo ufw logging on $ sudo ufw enable $ sudo ufw status Firewall loaded |
== UFW in Ubuntu == Ubuntu 8.04 LTS introduced `ufw`, and it is available by default in all Ubuntu installations after 8.04 LTS. |
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| To Action From -- ------ ---- 22:tcp ALLOW Anywhere }}} |
=== Available Versions === * '''Ubuntu 8.04 LTS''': 0.16.2 * '''Ubuntu 8.10''': 0.23.2 * '''Ubuntu 9.04''': 0.27-0ubuntu2 |
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| This sets up a default deny (DROP) firewall for incoming connections, with all outbound connections allowed with connections tracking. See [[https://wiki.ubuntu.com/UbuntuFirewall#More%20Information|More Information]] for full details. == Features == |
=== Features === `ufw` has the following features: |
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| == Basic Usage == Getting started with `ufw` is easy. For example, to enable firewall, allow ssh access, enable logging, and check the status of the firewall, perform:{{{ $ sudo ufw allow ssh/tcp $ sudo ufw logging on $ sudo ufw enable $ sudo ufw status Firewall loaded To Action From -- ------ ---- 22:tcp ALLOW Anywhere }}} This sets up a default deny (DROP) firewall for incoming connections, with all outbound connections allowed with connections tracking. === Advanced Functionality === As mentioned, the `ufw` framework is capable of doing anything that `iptables` can do. This is achieved by using several sets of rules files, which are nothing more than `iptables-restore` compatible text files. Fine-tuning `ufw` and/or adding additional `iptables` commands not offered via the `ufw` command is a matter of editing various text files: * '''/etc/defaults/ufw''': high level configuration, such as default policies, IPv6 support and kernel modules to use * '''/etc/ufw/before[6].rules''': rules in these files are evaluated before any rules added via the `ufw` command * '''/etc/ufw/after[6].rules''': rules in these files are evaluated after any rules added via the `ufw` command * '''/etc/ufw/sysctl.conf''': kernel network tunables * '''/var/lib/ufw/user[6].rules''': rules added via the `ufw` command (should not normally be edited by hand) * '''/etc/ufw/ufw.conf''': sets whether or not `ufw` is enabled on boot, and in 9.04 (ufw 0.27) and later, sets the LOGLEVEL After modifying any of the above files, activate the new setting with:{{{ $ sudo ufw disable $ sudo ufw enable }}} See [[https://wiki.ubuntu.com/UbuntuFirewall#More%20Information|More Information]] to learn more about the `ufw` command and the `ufw` framework. |
Introduction
The Linux kernel in Ubuntu provides a packet filtering system called netfilter, and the traditional interface for manipulating netfilter are the iptables suite of commands. iptables provide a complete firewall solution that is both highly configurable and highly flexible.
Becoming proficient in iptables takes time, and getting started with netfilter firewalling using only iptables can be a daunting task. As a result, many frontends for iptables have been created over the years, each trying to achieve a different result and targeting a different audience.
The Uncomplicated Firewall (ufw) is a frontend for iptables and is particularly well-suited for host-based firewalls. ufw provides a framework for managing netfilter, as well as a command-line interface for manipulating the firewall. ufw aims to provide an easy to use interface for people unfamiliar with firewall concepts, while at the same time simplifies complicated iptables commands to help an adminstrator who knows what he or she is doing. ufw is an upstream for other distributions and graphical frontends.
UFW in Ubuntu
Ubuntu 8.04 LTS introduced ufw, and it is available by default in all Ubuntu installations after 8.04 LTS.
Available Versions
Ubuntu 8.04 LTS: 0.16.2
Ubuntu 8.10: 0.23.2
Ubuntu 9.04: 0.27-0ubuntu2
Features
ufw has the following features:
Feature |
8.04 LTS |
8.10 |
9.04 |
default policy (allow/deny) |
yes |
yes |
yes |
allow/deny rules |
yes |
yes |
yes |
ipv6 |
yes |
yes |
yes |
status |
yes |
yes |
yes |
logging (on/off) |
yes |
yes |
yes |
application integration |
-- |
yes |
yes |
limit rules (rate limiting) |
-- |
yes |
yes |
multiport rules |
-- |
yes |
yes |
debconf/preseeding |
-- |
-- |
yes |
default policy (reject) |
-- |
-- |
yes |
reject rules |
-- |
-- |
yes |
rule insertion |
-- |
-- |
yes |
log levels |
-- |
-- |
yes |
per rule logging |
-- |
-- |
yes |
Basic Usage
Getting started with ufw is easy. For example, to enable firewall, allow ssh access, enable logging, and check the status of the firewall, perform:
$ sudo ufw allow ssh/tcp $ sudo ufw logging on $ sudo ufw enable $ sudo ufw status Firewall loaded To Action From -- ------ ---- 22:tcp ALLOW Anywhere
This sets up a default deny (DROP) firewall for incoming connections, with all outbound connections allowed with connections tracking.
Advanced Functionality
As mentioned, the ufw framework is capable of doing anything that iptables can do. This is achieved by using several sets of rules files, which are nothing more than iptables-restore compatible text files. Fine-tuning ufw and/or adding additional iptables commands not offered via the ufw command is a matter of editing various text files:
/etc/defaults/ufw: high level configuration, such as default policies, IPv6 support and kernel modules to use
/etc/ufw/before[6].rules: rules in these files are evaluated before any rules added via the ufw command
/etc/ufw/after[6].rules: rules in these files are evaluated after any rules added via the ufw command
/etc/ufw/sysctl.conf: kernel network tunables
/var/lib/ufw/user[6].rules: rules added via the ufw command (should not normally be edited by hand)
/etc/ufw/ufw.conf: sets whether or not ufw is enabled on boot, and in 9.04 (ufw 0.27) and later, sets the LOGLEVEL
After modifying any of the above files, activate the new setting with:
$ sudo ufw disable $ sudo ufw enable
See More Information to learn more about the ufw command and the ufw framework.
More Information
- Ubuntu 8.04 LTS (Hardy Heron)
- Ubuntu 8.10 (Intrepid Ibex)
- Ubuntu 9.04 (Jaunty Jackalope)
Specification: UbuntuFirewallSpec
UncomplicatedFirewall (last edited 2025-10-09 17:40:56 by hlibk)