My not-favorite firmware befuddled me once again.
I entered the office and powered on the router and network switches. The router is configured to send a wake-on-lan magic packet to the office computer a few feet away. This is a simple way for me to know the router, switches, and cables probably are functioning properly. Except the office computer did not power on.
I manually powered on the office computer and confirmed the router was not responding.
I grabbed the laptop and attempted to connect to the router with a DHCP network configuration. The laptop connected immediately. Not a good sign.
I opened a web browser and connected to the default 192.168.1.1 IP address. The router had reset to defaults and I was prompted to change the default credentials.
I restored the last router backup file and seemingly all was well again. Except later in the day I noticed the 5 GHz wireless configuration was broken and refused to configure. The 2.4 GHz configuration was fine. The 5 GHz configuration insisted on booting disabled.
I saw similar behavior when the router discombobulated itself.
I noticed in the configuration page the 5 GHz section heading showed
Wireless Physical Interface wl1 [2.4 GHz TurboQAM]. The heading should have shown
Wireless Physical Interface wl1 [5 GHz/802.11ac]. The MAC address was the same as the 2.4 GHz configuration. The
Wireless Network Mode would not show the
AC/N-Mixed option. There was a new option
TurboQAM (QAM256) support.
Manually setting options with
nvram set and
nvram commit made no difference. The web page would show the nvram changes, but a wireless SSID scan never showed the 5 GHz connection and the changes were not persistent across a reboot. The web page would not show a list of channels and only provided the
A frustrating challenge was often when I restored a backup file the router puked on reboot. I had to perform a hard reset to the defaults and begin from scratch.
One helpful person online pointed me to a note on the DD-WRT wiki that explained what I saw on my router, but the wiki provided no meaningful explanation about root cause.
The router sits on a high book shelf and is out of the way from probing fingers and curiosity. Nobody pressed any router buttons. There are no cats in the house. The router simply puked.
Contrary to the wiki instructions, I did not need to install an old version of the firmware. Yet every time I hard reset the router the initial 5 GHz wireless looked fine although refusing to configure.
I tried several different ways to restore the router. Eventually I surrendered. I restored my minimal base backup file. I manually recreated the remaining configurations throughout the router. Slow and irritating. I regularly rebooted the router after updating only a page or two. The router behaved.
I did not update the firmware. I continue to use the same version that has brought me the least grief. There might be unpatched exploits with such firmware, but there are no open WAN ports on the router. I am comfortable the router is reasonably secure. More important though is I am not a lab rat. I have no desire to continually update DD-WRT pretending to seek nirvana or some kind of Holy Grail. Why the developers refuse to release an official stable version is a mystery.
I have no idea what happened. I do not know why the router arbitrarily puked. I do not know what is corrupted in the backup files that causes the router to reset to defaults. My guess is a problem with nvram, but I am not going to spend time to find a definitive answer.
I really need to get motivated to build my own router/gateway.