Good Morning from my Robotics Lab! This is Shadow_8472, and if you missed last week’s post, feel free to check it out. It… was a minor disaster. I tried setting up PiHole network adblocker, but my home router unexpectedly moved its local IP address in the process. I cleaned up what I could really quickly and noticed my little hackjob of a subnet router was running an end-of-life operating system. Today, I am fixing that oversight. Let’s get started!
Replacing My Hackjob Router
Hackjob Router was my consolation prize after a failed quest to implement the open source router firmware, OpenWRT, onto my Raspberry Pi 4B in early 2020 and another in 2021. Both times, the exact version I needed was still under development. Dealing with testing versions was too advanced of a magic spell for me. I did, however, find an easy tutorial within my reach, but it did little to advance me beyond an aspiring networking mage with smoke and mirrors, but no fire or glass. When I looked this week, the beta warning was lifted.
I downloaded OpenWRT and flashed it over Hackjob Router’s SD card. Sure enough, the web interface was complete. I’ve used at least half a dozen ranging from limited config options to full access. OpenWRT’s “Lu-Ci” web interface puts everything on display with a helpful tool tip. It is comparable to other network devices I’ve worked with, but is simpler to look at, and has slightly more functionality.
My final configuration was surprisingly easy for a project that’s been hanging for almost three years now. At no point did I gain a key insight directly from an online search. But mistakes were made, and background information was researched and shelved for later.
My first mistake was a wrong Wi-Fi password. When I finally located and corrected it, my connection to OpenWRT died. I quickly learned how to assign a static IP in KDE’s settings thanks to intuitive interface design. I researched br-lan, a virtual network interface used for assigning one IP to multiple physical interfaces, thinking I needed to add the physical Wi-Fi radio to the one automatically generated to host all of the one Ethernet port and “bridge” the two sides that way.
The problem was actually a bad netmask. IPv4 network addresses come in four eight-bit numbers between 0 and 255. Local networks mask off leading bits – typically in multiples of 8 (for example: 10.0.0.1/8). Routers can use DHCP to dynamically assign local IP addresses with in their assigned subnet. My subnet ranges between 192.168.1.0 and 192.168.1.255 – properly denoted 192.168.1.1/24. Originally, my trailing mask was /16, allowing DHCP to assign my workstation to 192.168.0.200. Correcting the mask made it behave.
An unanchored memory I have regarding this week’s research is that some devices can route packets directly between network interfaces as opposed to routing them manually. I doubt the Raspberry Pi 4 has this ability, but it would be nice to know for sure.
Takeaway
Networking is magic at times. I still have a long way to go before I understand enough to do everything I want to, but I’ve cleared a large and long-standing burrier toward that goal this week. This is in part thanks to OpenWRT’s Lu-Ci with its educational help tips about every drop-down menu, text field, and tick box.
Final Question
Do you ever study a known science and everything inside you insists it’s magic?
I look forward hearing your answers on in the comments below or on my Socials.