The Sysadmin’s Daily Grind: Arpalert
ARP WATCH
Corporate policies prohibit the unauthorized connection of hardware to the company network, threatening dire consequences in the case of non-compliance. Fair enough, but how do you actually go about catching somebody trying to plug an illegal laptop into your Ethernet?
My choice for a faithful watchdog is Arpalert [1]. Arpalert creator Thierry Fournier recommends the following incantation to send the beast off into the wild: ./configure --prefix=/usr/local make make install This series of commands puts the C program in /usr/local/sbin and the arpalert.conf configuration file in /usr/local/etc/arpalert. No Place Like Home For my initial experiments, I decided to use a network that gives me excellent visibility, such as the network in my home office. It’s the weekend, and my wife has gone down to the local library, so I shouldn’t have more than four of five computers on the network. I did the following to launch Arpalert: /usr/local/sbin/arpalert
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
-
Linux Mint 22.2 Beta Available for Testing
Some interesting new additions and improvements are coming to Linux Mint. Check out the Linux Mint 22.2 Beta to give it a test run.
-
Debian 13.0 Officially Released
After two years of development, the latest iteration of Debian is now available with plenty of under-the-hood improvements.
-
Upcoming Changes for MXLinux
MXLinux 25 has plenty in store to please all types of users.
-
A New Linux AI Assistant in Town
Newelle, a Linux AI assistant, works with different LLMs and includes document parsing and profiles.
-
Linux Kernel 6.16 Released with Minor Fixes
The latest Linux kernel doesn't really include any big-ticket features, just a lot of lines of code.
-
EU Sovereign Tech Fund Gains Traction
OpenForum Europe recently released a report regarding a sovereign tech fund with backing from several significant entities.
-
FreeBSD Promises a Full Desktop Installer
FreeBSD has lacked an option to include a full desktop environment during installation.
-
Linux Hits an Important Milestone
If you pay attention to the news in the Linux-sphere, you've probably heard that the open source operating system recently crashed through a ceiling no one thought possible.
-
Plasma Bigscreen Returns
A developer discovered that the Plasma Bigscreen feature had been sitting untouched, so he decided to do something about it.
-
CachyOS Now Lets Users Choose Their Shell
Imagine getting the opportunity to select which shell you want during the installation of your favorite Linux distribution. That's now a thing.