Basic Troubleshooting
If we get a message like "No response from server" then you are most likely out of server
connections. You have reached the maximum number of connections allowed by your software
license. You can check this by going to the Fileserver and using the Monitor program to check the
Total number of connections against the number of licensed connections. ALT -ESC will cycle
through the loaded NLM’s and the console prompt. If the Monitor utility is not loaded, you can load it
using the command LOAD MONITOR.
If we get the message like “Error Finding Server” then there are several possiblities:
there is no working fileserver on the network
there is a problem with the cabling on that particular segment
there is a problem with the Fileserver network card attached to the segment
there is a problem with the network card in a workstation
- Check that there is a Fileserver running on the network - it may have been turned off or
abnormally ended (abended) its operation - stopped working due to some fatal error that has
occurred. If this is the case you can restart the Fileserver by pressing the reset button or turning it
back on again. If the cause of the problem was an abend or some such problem which caused the
server to cease operation and not shut down properly (i.e. closing all open files before exiting),
then you should run the VREPAIR utility on the network volumes to fix any errors which may
have occurred. VREPAIR is usually automatically run on 3.12 Fileservers.
If the Novell volumes have mounted, then type LOAD VREPAIR to load the Vrepair utility
(VREPAIR.NLM). Cycle back to the console screen (with ALT-ESC), and dismount each volume
using DISMOUNT ALL. Then cycle back to the VREPAIR screen and select Repair a volume.
Select each volume in turn to be repaired. If errors are detected on a volume, accept the suggested
changes and then run Vrepair on that volume again (repeat until no errors are reported on the
volume). Lastly, when all repairs are done, remount the volumes by typing MOUNT ALL.
- If you have a cabling problem then you need to determine where the fault is in the cabling.
STAR NETWORK This is easy in a star network as if the problem is only on one computer
then the problem is in the section of cable between the computer and
the hub, or the connector to the network card, or the network card or
the socket at the hub. Switch the connector and then the socket being
used at the hub to eliminate these and then try a different network card
in the computer. If this doesn’t work then try another temporary cable
from the computer to the hub. If that doesn’t work then try putting the
NIC into a different slot in the computer. One of these should have
fixed the problem.
If the problem occurs on all the computers then the problem is with the
cable between the Fileserver and the hub, the card in the Fileserver or
the hub.
LINEAR BUS All of the above still apply (except for the hub problem). In addition, to
troubleshoot this type of network layout we also need a 50 Ohm terminator
and a Mulitmeter. Terminate the network segment just after the connection to
the first computer in the network, from the Fileserver. Reboot this computer
and see if it connects to the network. If it doesn’t connect then try the network
cards in the computer and the Fileserver, the connectors and/or the cable
between the computer and the Fileserver If this computer connects to the
network then the problem is further out. Terminate further out and reboot the
computers between the terminator and the Fileserver. Keep doing this until
you isolate where the problem is occurring.
You can also use a Multimeter to try to find where the problem is in the
network cabling. Disconnect the two cables connecting the computer to the
sockets in the wall, at about the half way mark in the network. Set the
Multimeter to Ohms and read the value at each connection point. The reading
should be about 50 Ohms, if everything is OK. If you get 0 Ohms then there
is a short in the cabling or the connectors. If you get an infinite reading then
there is a break in the cable or connector. Reconnect the point and
progressively move down the side where the problem has been detected and
disconnect the cables and check each point. Eventually you will be able to
determine where the problem is.
If you are still having problems, check the backbone, by removing all the
patch leads from the wall plate connectors to the computers EXCEPT FOR
THE LAST COMPUTER on the cable segment. Then use one of each pair of
fly leads for each computer to connect the two wall plate sockets together for
that computer. Then reboot the last computer and see if it connects to the
network. If it doesn’t, use the terminator or multimeter to determine where
the problem is. (This eliminates the T-pieces, NICS except the one in the
Fileserver and last computer, computers and half the fly leads (from the wall
socket to the computer). If this is OK then test each of the remaining fly leads
to eliminate these. Then reconnect the computers one at a time, until you
strike the problem.
- If there is a problem which is occurring on many or all of the computers on a segment and
you cannot solve the problem by terminating and/or using a Multimeter, then try changing the
card in the Fileserver as this may be causing the problem. You will have to turn the server off
before doing this. Notify all users that this is going to happen, type DOWN to close all files and
dismount all volumes, then type EXIT and finally switch the Fileserver off. Replace the card and
then turn the Fileserver on again. If the problem is solved then the card is faulty. If you suspect it
could be the card, replace it with a card that you know is good and see if the problem persits.
- If a particular computer is having problems then it could be the network card in the
computer. Replace it and see if the problem persists. If there are intermittent faults on the
network, it could also be a network card in a computer.
If you still cannot determine where the problem is call in a cabling expert with the correct equipment
to test cables.
Monitor what is happening at the NICs in the Fileserver. This is done by
using the LAN statistics option in the MONITOR utility. After selecting this option, pick the network
card that you want check using the arrow keys, and when the desired card is highlighted, press the
ENTER key.
You will now be shown statistics for the particular network card. What is displayed varies from card
to card and depends upon the driver for that card.
You should look at any ERROR statistics that are given as these will give you clues as to what is
happening. For example, if the Card Reset Count is not zero then something is causing the card to
reset itself. It could mean a faulty card in the server. If the COLLISIONS COUNT is high, then there
is too much traffic on the particular segment and steps need to be taken to decrease the number of
computers that this card services. You could also have the case here where Windows has been set up
on the workstations so that the swap files on the Fileserver. This is not a desirable setup and will need
to be changed. If there are no hard drives in the workstations, then Windows should not have a swap
file in operation.
|
