2020-05-01 Probable lightning damage to a network switch
Today I noticed weird problems with the network in a desktop computer. It kept losing packets on the local network, with other computers in the same switch having no problems. In the end I switched to a different networkcard in the same computer to get rid of the problem. And that solved the problem. The most probable reason is a lightning storm that came very close yesterday evening. Update: The original 'suspect' was an Intel E1000 network card which had the first problems so I changed to a different card in the same computer. A week or so later similar problems started happening with a different computer on the same switch. I changed the switch which made the problem go away. On opening the suspect switch I saw a capacitor with a big bulge on the top so the internal power is probably unstable, which can be the root cause of really weird problems. Update: The replacement switch has only 5 ports, so I ordered an 8-port switch (my home office needs enough ports). After putting the 8-port switch in place I tested with the Intel E1000 again and it worked fine.