Hitting trains has become the new normal for russians.
It happened before but not with such regularity.
Traveling within the country has become restricted (many train routes no longer operate due to safety concerns) and a very dangerous endeavor.
And #RussiaIsATerroristState
The only other issues I would think are some kind of corrupt driver or broken Ethernet port... Both are pretty rare tho.
DHCP is just a server, cables won't change that, and messing around with other settings is relatively pointless because it's an automatic system.
I have had routers that have gone bad with weird glitches like this. The only way was to reset them, which was only a temp fix.
Next step then, use a Linux live CD and see if it gets an IP when running.
"Hell hath no wrath like a liberal who finally finds a woman they're allowed to hate on".
I would have gone with "leftist" instead of "Liberal" but still banger quote by @notsoErudite.