Ethernet socket woes

Steveocee · 12 May 2015 at 12:59

I'll pop this in here as it's network orientated.

Problem with my work laptop, a Lenovo X220 running Ubuntu 14.04. The onboard ethernet works with most kit we use but refuses to see a link to one particular model of kit.

The kit is connected in exactly the same way as any other but when connecting the laptop just doesn't see a link to it. I've tried all manners of trying to force it but it simply doesn't happen. Ethtool doesn't see a negotiated link so I'm fairly confident this is at hardware level/

If I use a cheapy £2 USB to ethernet adapter it sees said pieces of equipment so I know it isn't broken kit and we deploy on average 3 a day so they can't all be faulty.

Any advice or ideas on what I can do as the £2 job isn't going to last too long in the environment its in?

bledd · 12 May 2015 at 14:06

Any pins bent?

Steveocee · 12 May 2015 at 14:09

Nope, absolutely fine. Tried with different patch cables to different POE injectors and different cables between POE injector and "trouble" kit.

If I connect to a router I get a connection and a DHCP IP fine. Connect to a UBNT NSM5 and it works fine, connect to a UBNT PBM5-400 and nothing, oddly a rocket works though.

Jez · 12 May 2015 at 14:38

My first quick port of call would be to eliminate software level before you try anything else, boot into a WinPE environment or something just to test

Steveocee · 12 May 2015 at 16:02

Managed to sort it. Some weird auto negotiation issue. Forced 100Mb and it works. Thanks

Caged · 12 May 2015 at 19:30

You did try swapping the cable out didn't you?

Steveocee · 12 May 2015 at 19:58

Yes multiples of. Turns out the pbm has gigabit and so does my laptop bit the Poe adapters are 100mb and laptop was having a fit due to that.

Quick ethtool line to force 100mb and it appears.