Ethernet stopped working after a few months

[sigmamiller]

Hello,

I've been using the Pi for a few months now and just recently (last night) the ethernet stopped working. I have been working on some code to communicate with a FLIR A35 infrared camera via ethernet and in order to discover the camera, I needed to send out a UDP broadcast to which the camera would respond. I tested my UDP code first by connecting the Pi to my laptop and then used a packet sniffer on the laptop to see the UDP broadcast from the Pi. When I got that working, I connected the camera to a power over ethernet adapter (needed to power the camera) and then connected the other end of the adapter to the Pi's ethernet port. When I tried to send the same broadcast, sendto() erred with "Cannot reach the destination network." After fiddling around with the Pi, I noticed that the FDX, LNK, and 100 LEDs were constantly on, even when the ethernet cable was unplugged. So, I rebooted the Pi but the LEDs were still on and I could no longer connect to the internet through my router (wired to the router). Defeated, I did a clean install Raspbian today (Release Date 2014-01-07) but the LEDs are still constantly on and I still cannot connect to my router. I checked the voltage across TP1 and TP2 and it was 4.98V and the voltage drop across the F3 polyfuse was something like 0.02V. It should also be noted that I am not having any problems with the USB ports.

Heres my most recent dmesg output: http://pastebin.com/iUhZciYX. I also have a ifconfig output http://pastebin.com/d75zZb6Y. In addition, I tailed the syslog while I did 'ifdown eth0' and then 'ifup eth0': http://pastebin.com/MdjNRS3p (I just noticed that the system date and time are incorrect, all of these were from today).

I'm starting to feel like I'm going to have to buy another Pi, but I want to see if anyone has any ideas first.

[DougieLawson]

Start by connecting it to your router with a different cable.

[sigmamiller]

I tried a different cable but no success.

[Richard-TX]

If you changed the time on the pi (backwards in time) and did not reboot, then that can cause all manner of issues with TCP/IP.

I suspect that when you connected the POE adapter to the PI it damaged the Pi.

[ripat]

There is nothing wrong with your eth0 interface. It's up and running. The problem is that the eth0 iface is set to request an IP to a DHCP server but you connected it directly to the camera if I understand correctly your post. You can bypass your router that way but you need to:

1- give your camera and RPi a fixed IP's
2- manually populate the arp tables so that your Pi knows what mac address correspond to which IP.

The easy way: connect your camera and the Pi to a router which will manage all that.

[superkojot]

Hello,
I am facing the same issue - after same time of using of the raspberry PI ethernet stopped working. Now even if the ethernet cable is disconnected all three (FDX, LINK, 100M) are shining. Have you already solved your issue?