Why Isn't My Ethernet Working?

Question

I just got Pi Model B. I downloaded Wheezy on SD card and plugged in all of my cords. Everything works fine except the Ethernet port.

The LINK LED flickers for a second while booting up, but then it doesn't do anything and they stay OFF. The browser shows NO CONNECTION.

I checked the cable, and when connected to laptop it shows connections, so the cable is still good.

I tried using 1A and 700mA power supplies as few people had suggested, but it didn't work.

I tried removing USB wireless keyboard / mouse, as it may drain power. Didn't work either. I tried removing HDMI too; it didn't work.

I had ordered 2 units from UK. 1 for me and 1 for my friend. The Unit I gave to my friend is working fine on ArchLinux and everything from SSH is working fine on that.

Can it be hardware problem? If yes can I use any WiFi adapters over USB?

I haven't tried the deep freeze method few suggested (keeping the Pi in fridge for couple of hours seem to make USB / Ethernet work for some folks) but I don't want to do it as it may damage the board.

Answer 1

Please show the output of ifconfig -a and dmesg|grep eth0

By the way, it's easy to setup USB WiFi: plug in a compatible adapter, check if you see it as "wlan0" in ifconfig -a output (with HWaddr etc), modify 'wlan0' section in /etc/network/interfaces (assuming you're using WPA/WPA2 password-protected network with DHCP), then reboot:

allow-hotplug wlan0
iface wlan0 inet dhcp
wpa-ssid "YOUR NETWORK NAME"
wpa-psk "YOUR PASSWORD"

Answer 2

I though problem was that I was using a cheaper CAT5 cable, so I changed it with the one that came with my router.

Solution :

And gave a nudge to X1 crystal. And voila ! LINK LEDs lit up like Christmas tree :)

Now Ethernet works with both cables.

Problem (I'm just guessing) :

So I am assuming that there was loose soldering near X1 and it was not oscillating.

Answer 3

I had a similar problem, Laptop worked ok when plugged into Ethernet - pi didn't (flashing lights only) using the same cables.

In the end, I opened the Ethernet port (RJ45 socket in the wall) and a couple of the cables were not punched down correctly - punched in, and it is all working.