25 Replies Latest reply on Apr 17, 2017 1:03 AM by ktjr

    Raspberry Pi Ethernet Problem

    ejf128

      Whenever I turn my Raspberry Pi on, the three network lights just blink and it can't connect to the internet. I have checked all network items and they do work so it comes down to the Raspberry Pi.  Is there something physicaly wrong with the board itself?

       

      It is Model B and I have Wheezy installed on the SD card if that helps or makes a difference at all.

        • Re: Raspberry Pi Ethernet Problem
          christian.semmens@gmail.com

          Hi Eric,

           

          You say you have "checked all the network items", but you don't say what these are or how you checked them.

           

          Are you using an ehternet cable to connect the Pi into your router, or are you trying to use a USB WiFi dongle?

           

          If you are trying to use WiFi, get an ethernet cable and use that first.

           

          If you are using a cable are you plugging it directly into your router or into a separate switch?

           

          What is the router you are using?

           

          Have you tested your ethernet cable with another device, like a laptop, to make sure it works OK?

           

          Christian

            • Re: Raspberry Pi Ethernet Problem
              ejf128

              It uses a wired connection. I have ran other computers on the same hub port with the same ethernet cable and they connect to the internet without a problem. I have tried connecting the raspberry pi directly to my cable modem using the same cable that was tested with other computers and still the three network lights on the raspberry pi just blink repeatedly without connecting.  What would cause all 3 lights to blink? 

                • Re: Raspberry Pi Ethernet Problem
                  christian.semmens@gmail.com

                  Ah, cable, do you have a separate hub connected to the cable modem? Or does the cable modem have a built-in hub?

                   

                  When you connect the Pi to your hub and power it on, does the hub port light come on?

                   

                  We also need the answer to Gary's question. Open a Terminal and type:

                   

                  ifconfig

                   

                  Then post us what the terminal replies.

                   

                  You should see something like this:

                  eth0  Link encap:Ethernet  HWaddr A4:BA:DB:0E:4B:5A 
                        inet addr:192.168.1.15  Bcast:192.168.1.255  Mask:255.255.255.0
                        inet6 addr: fe80::a6ba:dbff:fe0e:4b5a/64 Scope:Link
                        UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
                        RX packets:511774773 errors:1 dropped:0 overruns:0 frame:1
                        TX packets:62692741 errors:0 dropped:0 overruns:0 carrier:0
                        collisions:0 txqueuelen:1000
                        RX bytes:94801773297 (88.2 GiB)  TX bytes:56854688675 (52.9 GiB)
                        Interrupt:82 Memory:da000000-da012800

                   

                  lo    Link encap:Local Loopback 
                        inet addr:127.0.0.1  Mask:255.0.0.0
                        inet6 addr: ::1/128 Scope:Host
                        UP LOOPBACK RUNNING  MTU:16436  Metric:1
                        RX packets:12584915 errors:0 dropped:0 overruns:0 frame:0
                        TX packets:12584915 errors:0 dropped:0 overruns:0 carrier:0
                        collisions:0 txqueuelen:0
                        RX bytes:8041559088 (7.4 GiB)  TX bytes:8041559088 (7.4 GiB)
              • Re: Raspberry Pi Ethernet Problem
                ejf128

                I checked. It is enabled.

                • Re: Raspberry Pi Ethernet Problem
                  christian.semmens@gmail.com

                  In that case it seems that the network device is OK. Try manually setting the network configuration.

                  Use your favourite editor on /etc/network/interfaces file. Make sure it looks like this:

                   

                  auto eth0

                  iface eth0 inet dhcp

                   

                  If that works, you should be good to go. If that doesn't work then set the IP address manually, you need to know the subnet, usually 192.168.0.0 or 192.168.1.0, and your router IP address,

                   

                  auto eth0

                      iface eth0 inet static

                          address 192.168.0.55

                          netmask 255.255.255.0

                          gateway 192.168.0.254

                   

                  If this works you should have network connection, man interfaces should give you more information on this file should you need it.

                   

                  This will test whether you can get a network configuration loaded. If you can then se if you can ping your router.

                    • Re: Raspberry Pi Ethernet Problem
                      ejf128

                      I tried both. By setting it to DHCP, upon reboot it just searched several times for an IP address but never got one. I tried to ping once it rebooted and nothng. I also tried setting a static IP as you said and nothing for a ping still. Perhaps something is physically wrong with the ethernet port?

                        • Re: Raspberry Pi Ethernet Problem
                          christian.semmens@gmail.com

                          That is possibility, but more likely it is your ethernet cable. Test that on a workimg system just to discount it.

                           

                          Also try one of the other distributions or an updated copy of Raspbian from here http://www.raspberrypi.org/downloads

                          (you didn't say what version you were running).

                           

                          Also check your router is actually sending DHCP out on the ethernet port (you didn't mention what router you had).

                           

                          If you have managed to configure a static IP address properly can you post the output of ifconfig please. Also can you ensure that your chosen IP address is on the same subnet as the router (sorry if this is basic stuff, but I don't like to make assumptions about your experience level as you haven't said).

                           

                          Another trick is to connect another device into the wired network and try that out. Once you have a working connection on that device try connecting to the Pi or vice versa. It would be useful if you could also post the output of ipconfig /a from any Windows device you have connected, or ifconfig from a Mac or Linux terminal session on the other device.

                           

                          Ethernet ports are usually quite reliable. Mostly it is bad cables, dodgy DHCP configurations or problems with the arbitration of a connection speed with the switch/hub. On that subject what is your switch/hub (manufacturer and model)?

                           

                          Please also list your IP address configuration for the internal network of your router, Pi and other wire connected computing device, just so we are clear that everything is OK.

                           

                          Christian

                          • Re: Raspberry Pi Ethernet Problem
                            John Beetem

                            Eric Finendale wrote:

                             

                            I tried both. By setting it to DHCP, upon reboot it just searched several times for an IP address but never got one. I tried to ping once it rebooted and nothng. I also tried setting a static IP as you said and nothing for a ping still. Perhaps something is physically wrong with the ethernet port?

                            The LEDs blinking might mean that the Ethernet port is trying to auto-negotiate and/or auto-MDIX (exchanging the RX and TX pairs so it doesn't matter what kind of cable you have plugged in) and is failing due to a bad Ethernet cable or physically bad Ethernet jack on the RasPi.  Check it carefully with a strong light to make sure the pins look good, and check the discrete resistors and capacitors near the Ethernet jack for bad solder joints and missing components.  Make sure the Ethernet jack pins actually go through the board and are soldered properly.  (A long shot is that the manufacturer used the wrong kind of Ethernet magjack, but that's pretty unlikely.)

                             

                            If trying to ping RasPi causes it to reboot you may have a hardware problem.  Check the TP1-TP2 voltage, since iffy power supplies can cause all sorts of RasPi problems: see the RasPi Troubleshooting Wiki here and here.

                             

                            Another possibility is a bad OS image.  You might try rewriting the OS image onto your SD card.

                             

                            If none of these work, it might be a bad solder joint or cracked PC board trace somewhere and you should RMA.

                        • Re: Raspberry Pi Ethernet Problem
                          jimX

                          Assume you've probably got things to work by now...

                           

                          I think I just ran into a similar problem in getting my networking to go as well.

                           

                          Note: I had the additional complication of MAC filtering turned on in my router so I needed to get that all set up first on the router. As well I have DHCP, but with assigned addresses also taken care of on the router (although it should provide any freely available one, I like having the same machine on the same address).

                           

                          So after doing all that I expected things to start right up as any other device I've ever connected to my router.

                           

                          What finally got things working was bringing the eth0 interface down and up using the following commands;

                           

                          ifdown eth0

                          ifup eth0

                           

                          Then do the ifconfig and you should see IP addresses assigned to the PI

                           

                          Final note: I had tried rebooting the Pi and restarting the interface none of which worked for me, but you can try the command to restart the network interface services as follows;

                          /etc/init.d/networking restart

                            • Re: Raspberry Pi Ethernet Problem
                              ejf128

                              Sorry but i haven't fixed the issue yet. I was just out of town for the weekend. I did try a different computer on the same jack which worked fine for the internet. I tried putting a new image of wheezy on it but still no solution. I can try to post my windows configuration from ipconfig later today when i get a chance along with trying the ipdown.

                                • Re: Raspberry Pi Ethernet Problem
                                  erhep

                                  I just got my Raspeberry Pi unit today and started looking for a solution to this problem myself. After spending some time looking for the answer I decided to try another cable; even though the first cable was used to connect one of my computers to the internet. Strangely enough it worked just fine when I switched to another cable.

                                  I can't say what causes this behaviour, but it seems like even though the cable works on my laptop it may not work on the Raspberry Pi. Switching to another cable could be helpful despite the cable seems to be working fine. (The LED's on the Pi was on and flickering so I thought everything was OK.)

                                   

                                  I guess the Raspberry Pi might be more strict about the cable than my laptop. If anyone have an answer to why this happens I would like to know.

                                    • Re: Raspberry Pi Ethernet Problem
                                      John Beetem

                                      Erik Hepso wrote:

                                       

                                      I just got my Raspeberry Pi unit today and started looking for a solution to this problem myself. After spending some time looking for the answer I decided to try another cable; even though the first cable was used to connect one of my computers to the internet. Strangely enough it worked just fine when I switched to another cable.

                                      I can't say what causes this behaviour, but it seems like even though the cable works on my laptop it may not work on the Raspberry Pi. Switching to another cable could be helpful despite the cable seems to be working fine. (The LED's on the Pi was on and flickering so I thought everything was OK.)

                                       

                                      I guess the Raspberry Pi might be more strict about the cable than my laptop. If anyone have an answer to why this happens I would like to know.

                                      Here's my experience: 10/100baseT Ethernet uses twisted differential pairs for RX and TX.  If one side of a pair breaks, some signal still gets through, but with poor signal quality.  Depending on the receiver and cable length, you may be able to get enough frames  through to operate.  Some PHY chips do a better job than others with poor signals.  TCP and other protocols re-transmit if packets don't get through, so as long as some packets get through you still get a connection, though it can be very slow.

                                        • Re: Raspberry Pi Ethernet Problem
                                          erhep

                                          John Beetem wrote:

                                           

                                          Here's my experience: 10/100baseT Ethernet uses twisted differential pairs for RX and TX.  If one side of a pair breaks, some signal still gets through, but with poor signal quality.  Depending on the receiver and cable length, you may be able to get enough frames  through to operate.  Some PHY chips do a better job than others with poor signals.  TCP and other protocols re-transmit if packets don't get through, so as long as some packets get through you still get a connection, though it can be very slow.

                                          Thanks for the answer John.

                                          That sounds plausible. I always thought it was either working or not.

                                          I better check my cables, and perhaps start treating them nicer too.

                                            • Re: Raspberry Pi Ethernet Problem
                                              ejf128

                                              I inspected the board this weekend and found that resistor 50 is missing!  Could this be why it won't connect?  Also if this is the case does the RMA cover a situation like this? or could I repair it if I can solder that tiny?

                                                • Re: Raspberry Pi Ethernet Problem
                                                  John Beetem

                                                  According to the RasPi schematics, R50 connects the SD card DAT1 signal.  This should only affect SD card behavior, and then only if the SD card is using a 4-bit data bus.  If your RasPi is booting, then either your SD card doesn't use 4-bit mode or RasPi's software has detected errors using 4-bit mode and has fallen back to 1-bit mode.

                                                   

                                                  You can replace R50 if you have a soldering iron with a small tip and a good pair of tweezers.  However, board modifications generally void the warranty -- I don't know about if doing your own repairs counts as a "modification".  The absence of R50 does suggest that your board slipped through quality control, so who knows what else might be wrong with it?  From what I read, RasPi boards don't go through a lot of Q/C but suppliers tend to be good about replacing defective units.

                                                    • Re: Raspberry Pi Ethernet Problem
                                                      ejf128

                                                      Just as a follow up for anyone who reads this thread in the future and for all of you helpers...

                                                       

                                                      I had ordered another raspberry pi and just reimaged the sd card, booted up in that one, and the internet worked fine.  I took the sd card out and put it in the old raspberry pi and hooked up the same exact cables and ethernet cord but it still didn't work. With that and the missing resistor I am definitely going to RMA it.  Thank you all for your help!

                                        • Re: Raspberry Pi Ethernet Problem
                                          uk4tech

                                          Hi,

                                           

                                          I had the same problem. I was trying to connect to the internet for the first time. I did the same things. Set static address, restarted the pi. Finally the 'ifdown' and 'ifup' did the trick. I had to use "sudo ifdown eth0". Without the sudo I got a permission error.

                                           

                                          Thanks you all for the help.

                                            • Re: Raspberry Pi Ethernet Problem
                                              sidebar

                                              I also am having problems with a Raspberry Pi (a B+). Did have a connection with a wifi adaptor but that broke and will be going back. Tried plugging in an ethernet cable and the hub appears to be seeing the Pi but the Pi says that there is no internet connection. Tried 'sudo ifdown eth0' followed by 'sudo ifup eth0' and got a series of DHCPDISCOVER messages followed by 'No DHCPOFFERS received'. ifconfig shows no internet address against eth0.

                                               

                                              Any help would be really appreciated.

                                            • Re: Raspberry Pi Ethernet Problem
                                              engglucky

                                              Hello Eric I am facing great problem in raspberry. I need to make my raspberry pi as a hotspot device. For this i am using so many links but i am unable to this task.

                                              I am posting the same link from where i am taking help.

                                              Hotspot – WiFi Access Point | Raspberry-at-home.com – Your ultimate source of Raspberry Pi tutorials (WiFi, 3G, XBMC, Su…

                                              I will be so glad if u give me any type of assistance....

                                              Waiting fr ur reply.....