Logitech Arx Control: A Great Way to Spam Your Own Network

Just a couple days ago, Windows 10 on my gaming desktop decided that I needed to clean it up. I know this by the fact that when I rebooted, it claimed it couldn't find the OS. It did this from a blue screen that looked like Windows 10, so I don't quite believe that it was completely gone. That said, I'm also not sure what the Windows 10 recovery partition is capable of, so maybe it's all provided from that.

Windows 10 Score:

• Allowing me to perform reset without having to do a full re-install of Windows 10: +10
• Allowing itself to be corrupted in the first place: -9001

After the reset finished, I had a fairly clean version of stock Windows 10 (though upgraded with the latest patches). That means no applications were installed except for the ones that come with Windows. (During the reset, Windows 10 did create an HTML page on my desktop that listed everything it removed. So maybe +12.)

On the plus side, several of the applications I regularly use were out of date, so this was an opportunity to move to the latest version. One of the applications that I had to reload is the Logitech Gaming Software, which my G602 mouse and C920 camera use. That's fine. However, by default, the software enables Arx Control. That's not fine.

I happened to look at my firewall logs and see that my internal network was getting flooded with message after message that all looked like:

Jan 15 18:32:44 gw16lts kernel: [  188.117713] (D)IN-drop: IN=enp7s0 OUT= MAC=ff:ff:ff:ff:ff:ff:34:97:f6:37:b2:eb:08:00 SRC=192.168.xxx.xxx DST=192.168.xxx.255 LEN=291 TOS=0x00 PREC=0x00 TTL=128 ID=15131 PROTO=UDP SPT=54915 DPT=54915 LEN=271

(Note I edited in the xxx's.) The first post returned from Google-ing UDP port 54915, gave the answer I needed. The culprit is Logitech's Arx Control application, which emits a stream of nearly constant broadcast requests looking for Android and iOS devices to talk to. That's all well and good if you use the application. I don't, and I never have. Therein lies the rub. It's on by default not off until you need it. Most people don't have nearly the firewall logging I have, so most won't even know this is happening. If you happen to have more than one machine with Logitech's Gaming Software, you've got a lot of unnecessary network traffic banging around inside your internal network. I don't know that it would slow your whole network down (as all machines on the network see all broadcasts), but it's not helping.

If you have this software installed and have not done this yet:

1. Open the Logitech Gaming Software application
2. Click on the Settings icon, which looks like a gear
3. Open the Arx Control tab
4. Uncheck the boxes under the Mobile Service labeled Enable and Automatic Discovery

I now know where my pain is going to come from for the next few weeks. I've reloaded all the applications that I still use. When I saw the post, I remembered that I had "fixed" this problem before. However, all those tiny little settings that make things work smoothly aren't documented anywhere. This is a start, I guess.