Troubleshooting the Network

SCENARIO 1: You cannot log in, and the computers that are already logged in cannot open matlab (they send a license error), you cannot open the shared folder or your personal folder

This means that something is wrong in between the workstations and the server. If you have detected this just in one computer, start by asking others if they are having the same problem.

1. If you are the only one with that problem, check that your computer was not disconnected from the network, try to reboot your computer (as it could be that the driver for your network card crashed).
2. If you detect that all the workstations share the same problem, it can have two sources of failure; it might be either that the server is malfunctioning or that the switch for the lab is malfunctioning

• If you know how to retrieve the ip address from your computer (with the ipconfig command on a DOS shell), and you know how to run a ping to another address, try to ping in between computers in the lab. If they can ping each other it means that the switch is OK (check the next case then), if they cannot, this is the worst case, as the switch is enclosed in a room controlled by IS, you have to call IS so they can reset the switch.
• You can ping between workstations, now try to ping the server (it is the default gateway address given by the ipconfig command ran above). If you cannot ping the server it means that there is no connectivity to the server. Check if the server was not disconnected from the network. If you can ping the server, or it was not disconnected from the network but the problems is still there, I recommend rebooting it (there is a small control panel in front of the server, you can reboot the server from there).

SCENARIO 2: You can log in, open Matlab, open the page to change you password, but you cannot browse the internet or download e-mails.

This means that there is a problem with the internet link or the routing of packets. First of all check if your applications is not the one that is failing (open a browser in another computer and try, try different websites, as you might have hit a site that went down, if you cannot browse, check if e-mail or a SSH session are working). If you detect that it is a general problem. Try to follow these steps:

• Check if the network cable that goes from the server to the Motorola modem (Rogers connection) is properly connected and if the link is up (you can check this on the Motorola modem’s LED’s as far as I remember)
• If the network cable is OK, disconnect the power from the Motorola modem (it is connected through a coax cable to the wall, and receives power from a DC power source, disconnect this one for some seconds and reconnect). Wait for some minutes, the first 5 lights must go on, if they don’t, it means that rogers is having problems in their equipment (it it lasts for a while you might need to call Rogers to find out what’s happening and how long it will last, and if it is just our connection or a generic problem)
• If none of these solve the problem, try rebooting the server (as described above), just in case that the routing algorithm got confused.
• If none of these work, you’ll have to call Rogers and report the problem. You may need some numbers that are written in the Motorola modem, probably the agreement or customer ID from Rogers, and probably the MAC address of the server.