View Physical Layer Errors?

[HarryMuscle]

I'm troubleshooting an issue and I think it might be a bad cable but it's a pain to rerun, so before I do so, I was wondering if it's possible to view somewhere on the router if there are any errors being reported at the physical layer of the network (which would confirm that it's a bad cable)? Are such errors logged in the router log? If they are, what do the log entries say? Or is there somewhere else I can check for physical errors between the router and a wired device?

Thanks,
Harry

 

[drinkingbird]

Ifconfig will tell you errors on the port. Note these won't be "physical layer" errors as the physical layer is just volts, the port will report layer 2 and layer 3 errors.

To test a cable, assuming you don't have an expensive fluke tester, put a PC on either end and use iperf. You should be able to get about 95% throughput using TCP. There are plenty of other utilities that will tell you packet drops etc but if you can get 95% with iperf, the cable is likely fine.