Troubleshooting School Servers
From OLPC
This is a simplistic and somewhat outdated guide to troubleshooting a School server. A more detailed quide to testing is available, as is a guide to school network debugging. This should be updated at some time in the future...
Contents |
[edit] Network Problems
This is a logic tree for debugging network accessibility using an XS School Server.
This is very much a work in progress. Feel free to correct and extend!
[edit] 1.1 Can XOs communicate with the Internet ?
Test (Build 406): Make sure that the laptop has associated itself with the school server. If you go to the "mesh view", there should be a circle shown. Click on the circle. It should start blinking, and after 5 minutes or so stop blinking and show a circle which is completely filled in.
Use the web browser to access google.com
If you can access google, you have access to the Internet.
If you cannot access google.com, proceed to question #1.2: Can XOs communicate with the server
[edit] 1.2 Can XOs communicate with the server ?
Now try to access http://172.18.0.1/ from the web browser
If a page appears, then communication over the mesh to the server is working, proceed to question #3: Is DNS working ? If DNS is working, then you have an unknown problem, please contact server-devel at laptop.org.
If you get an "Unable to contact server" or "Server not responding" message - the mesh isn't working, go to question #1.20: How is your XO configured ?
[edit] 1.3 Is DNS working ?
At a console, try typing ping www.test.com.
If see
ping: Unknown host www.test.com
then DNS is not working. Go to question #1.4: "Is DHCP working"
If you see something like:
PING www.test.com (64.214.163.132): 56 data bytes 64 bytes from 64.214.163.132: icmp_seq=0 ttl=116 time=44.760 ms 64 bytes from 64.214.163.132: icmp_seq=2 ttl=116 time=47.214 ms ...
then your DNS is configured and working.
[edit] 1.20 How is the XO configured ?
Test: Access an XO debugging console. Make sure that you have followed the mesh association instructions in question 1. Check that the laptop has associated itself with the mesh. Type "ifconfig", and you should see that interface msh0 has an IP address in the range 172.18.10.2 to 172.18.63.254. Type "ping 172.18.0.1" and you should see a response.
If you can ping the server, go to question 1.30. If the IP address isn't set to the proper range, or you can't succesfully ping the server, go to question 1.21: "Restart the server"
[edit] 1.21 Restart the server
Currently there is a problem with Active Antennas. Unless they have been fixed, they will not work unless plugged into the server after it has finished booting. A fix is available.
Turn it completely off (using the power switch in the back) and ensure that all active antennas are properly plugged in. Only the USB ports in the back of the server work. Turn it back on by turning on the power switch (and pressing the big button in the front if it doesn't automatically start up). Give it five minutes to come up and start testing again at question #1
If this doesn't solve the problem, there may be a number of causes: The server has a hardware failure, see question #90 Other WiFi access points are present, using the same channels used by the mesh.
