UncomplicatedFirewall
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| * Ubuntu 10.04 (Lucid Lynx) * [[https://help.ubuntu.com/10.04/serverguide/C/firewall.html|Server Guide - Firewall]] * [[http://manpages.ubuntu.com/manpages/lucid/en/man8/ufw.8.html|ufw manual]] * [[http://manpages.ubuntu.com/manpages/lucid/en/man8/ufw-framework.8.html|ufw framework manual]] |
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
Ubuntu 9.10: 0.29-2
Features
ufw has the following features:
Feature |
8.04 LTS |
8.10 |
9.04 |
9.10 |
10.04 LTS |
default incoming policy (allow/deny) |
yes |
yes |
yes |
yes |
yes |
allow/deny incoming rules |
yes |
yes |
yes |
yes |
yes |
ipv6 |
yes |
yes |
yes |
yes |
yes |
status |
yes |
yes |
yes |
yes |
yes |
logging (on/off) |
yes |
yes |
yes |
yes |
yes |
extensible framework |
yes |
yes |
yes |
yes |
yes |
application integration |
-- |
yes |
yes |
yes |
yes |
limit incoming rules (rate limiting) |
-- |
yes |
yes |
yes |
yes |
multiport incoming rules |
-- |
yes |
yes |
yes |
yes |
debconf/preseeding |
-- |
-- |
yes |
yes |
yes |
default incoming policy (reject) |
-- |
-- |
yes |
yes |
yes |
reject incoming rules |
-- |
-- |
yes |
yes |
yes |
rule insertion |
-- |
-- |
yes |
yes |
yes |
log levels |
-- |
-- |
yes |
yes |
yes |
per rule logging |
-- |
-- |
yes |
yes |
yes |
outgoing filtering (on par with incoming) |
-- |
-- |
-- |
yes |
yes |
filtering by interface |
-- |
-- |
-- |
yes |
yes |
bash completion |
-- |
-- |
-- |
yes |
yes |
upstart support |
-- |
-- |
-- |
yes |
yes |
improved reporting |
-- |
-- |
-- |
-- |
yes |
reset command |
-- |
-- |
-- |
-- |
yes |
rsyslog support |
-- |
-- |
-- |
-- |
yes |
delete by rule number |
-- |
-- |
-- |
-- |
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 state 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/default/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 or /lib/ufw/user[6].rules (0.28 and later): 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 settings with:
$ sudo ufw disable $ sudo ufw enable
More Information
- Ubuntu 8.04 LTS (Hardy Heron)
- Ubuntu 8.10 (Intrepid Ibex)
- Ubuntu 9.04 (Jaunty Jackalope)
- Ubuntu 9.10 (Karmic Koala)
- Ubuntu 10.04 (Lucid Lynx)
Specification: UbuntuFirewallSpec
UncomplicatedFirewall (last edited 2025-04-22 15:55:11 by ebarretto)