Graphical tools for firewall configuration
Shorewall
Shorewall [7] also relies on netfilter and iptables. The graphical management interface for filtering packages is written in Perl; packages are included in most major Linux distributions. Shorewall is suitable both for single workstations and for server systems, which can also be used as gateways with two network connections or in a DMZ with three network interfaces. Shorewall uses Webmin [20] as a GUI or the drakfirewall [21] graphical front end in Mandriva derivatives. This control center module supports configuration in just a few steps (Figure 11).
Webmin for distributions outside the Mandriva universe offers many more options for system administration than just configuring the firewall. After installing, you can access it in the browser from the 127.0.0.0.1:10000 URL. Alternatively, it specifies – if known – the IP address in the local intranet or the hostname.
After logging on, you find yourself in the configuration window. In the list area on the left, selecting Networking | Shoreline Firewall displays the individual configuration options on the right (Figure 12).
Group Dynamics
The most important options for the existing infrastructure's basic settings can be found in the Network Zones and Network Interfaces groups. These are joined by the firewall settings options in the Default Policies, Firewall Rules, and Blacklist Hosts groups. The options responsible for routing can be found in the Routing Rules, Additional Routing Providers, Masquerading, and Static NAT groups.
You will encounter clear setting dialogs in all configuration groups, which list the available options in tabular form. Below the group selection, you can enable various management options simply by clicking on one of the buttons available there: Clicking on Apply Configuration restarts the firewall with your settings.
The Refresh Configuration button updates the blacklist and traffic shaping tables, which ensures that the firewall prioritizes certain packets. If you want to reset the firewall settings, click on Clear Firewall. The Stop Firewall button blocks access from all hosts – with the exception of those excluded from the whitelist. The Show Status button tells you about the current operating status of Shorewall.
The Check Firewall button enables a consistency check: Many extensive iptables-based rules and regulations contain errors because of their complexity. They can be detected and fixed before being exploited by malicious attackers.
Logging
Shorewall can log the data traffic and stores the protocols in the /var/log/
directory. Alternatively, you can view the logfiles in Webmin with the View Module's Logs option (Figure 13).
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
TUXEDO Computers Unveils Linux Laptop Featuring AMD Ryzen CPU
This latest release is the first laptop to include the new CPU from Ryzen and Linux preinstalled.
-
XZ Gets the All-Clear
The back door xz vulnerability has been officially reverted for Fedora 40 and versions 38 and 39 were never affected.
-
Canonical Collaborates with Qualcomm on New Venture
This new joint effort is geared toward bringing Ubuntu and Ubuntu Core to Qualcomm-powered devices.
-
Kodi 21.0 Open-Source Entertainment Hub Released
After a year of development, the award-winning Kodi cross-platform, media center software is now available with many new additions and improvements.
-
Linux Usage Increases in Two Key Areas
If market share is your thing, you'll be happy to know that Linux is on the rise in two areas that, if they keep climbing, could have serious meaning for Linux's future.
-
Vulnerability Discovered in xz Libraries
An urgent alert for Fedora 40 has been posted and users should pay attention.
-
Canonical Bumps LTS Support to 12 years
If you're worried that your Ubuntu LTS release won't be supported long enough to last, Canonical has a surprise for you in the form of 12 years of security coverage.
-
Fedora 40 Beta Released Soon
With the official release of Fedora 40 coming in April, it's almost time to download the beta and see what's new.
-
New Pentesting Distribution to Compete with Kali Linux
SnoopGod is now available for your testing needs
-
Juno Computers Launches Another Linux Laptop
If you're looking for a powerhouse laptop that runs Ubuntu, the Juno Computers Neptune 17 v6 should be on your radar.