Chapter 5 - Troubleshooting an AppleTalk Network
This chapter outlines some tips for troubleshooting your AppleTalk network running under VINES. It is divided into the following sections:
General Check List - A quick list of things to check first.
Symptoms and Causes - A list of some commonly encountered symptoms, their causes, and how to correct the associated problems.
General Troubleshooting Tips - This section gives general tips for resolving problems, including performance problems.
If a specific error message is displayed on your server, look for the error message in the section "Symptoms and Causes".
In this chapter, we refer to VNSM, the VINES Network and Systems Management software. To reach the menus and screens for VNSM, follow these steps:
1. From the Operator Menu, choose Run Network Management.
2. Use the arrow keys to choose the server or servers you want to check from the list of available servers. Press F10. The VINES Network Summary menu appears. From this menu, choose the feature you want to use.
For more information on using VNSM, see Monitoring and Optimizing Servers.
If you have a problem with your software and don' t see a specific error message, check the items in this section. Checking them helps pinpoint the problem. This section is divided into three check lists:
What to check at the server What to check with cables What to check at the workstations
Checking these items at the server may help to solve unspecified network problems.
If you receive errors while attempting to start the AppleTalk software for the first time, check to see that you installed the option properly. See "Installing the VINES Option for Macintosh" in Chapter 3. - If the server contains no seed ports, make sure that there are seed ports on the network that it can reach to get its routing information.
- Are you using network number ranges or multiple zones in a network that contains both non-extended and extended LAN segments? A network that contains both non-extended and extended LAN segments cannot have network number ranges greater than zero or more than one zone per LAN segment.
After you started the AppleTalk software, did you wait long enough for the services to activate? Under some conditions, it may take more than 5 minutes from the time the port has successfully initialized until the file service shows up under Chooser. Is VINES AFP (AppleTalk Filing Protocol) still running? VINES AFP becomes inoperative if the AppleTalk software is not running within two hours of VINES AFP's starting. If the AppleTalk software was stopped for two hours or more, use OPERATE to restart VINES AFP. If you are using a VINES port, is the network number unique throughout the network? Look at the Display Port Status screen. If a status appears unusual (is not what is described as normal in "Displaying the Port Status" in Chapter 3), look at the operating system log for any unusual conditions. Make sure that all routers on the same LAN segment are using the same network range (or network number) and zone list (or zone name). If you have Inter·PollTM software (from Apple Computer, Inc.), use it to try to reach the server. (For example, Inter·Poll allows you to send echo packets to a server.) The documentation provided with the program should aid you in finding the problem.
Some network problems might be the result of faulty or incorrect cabling. This list describes some common cabling problems.
Check the cable connections at the back of the server. If they seem tightly connected, try disconnecting and reconnecting them to see if that helps. Was the cable connected to your Macintosh workstation when you activated the AppleTalk software, rebooted, or switched to another LAN segment? The Macintosh workstation uses dynamic node assignment, and must be able to communicate with all other nodes on the LAN segment so that it can pick a node number not already in use. On a small network, or on a network that you have isolated as having trouble, check the cables attached to the AppleTalk ports. Have you or anyone else recently touched the cables? Is it possible that cables might have been swapped? Are the cable ends terminated properly? For example, in a LocalTalk network, make sure that the connector at the end of the network does not have a stray cable connected to it (one that does not connect to a device). If you are using Farallon PhoneNET® , make sure that the terminating end contains a terminator.
You can verify the following conditions yourself, or ask a user to verify them at the workstation.
Did the user select the AppleShare icon in the Chooser? The user must select the AppleShare icon before a list of servers appears. Is the correct communications driver installed and selected? Use the Control Panel to verify this. (See "Installing Network Drivers" in Chapter 4 for more information.)
This section lists some error messages, some common symptoms, their causes, and how to correct the associated problems.
"--> Services stopped... please restart services"
This error can occur when you start AppleTalk. It means that some essential VINES services are not running. Use Restart Services from the Operator Menu to restart VINES services.
If this error occurs when services are already running, look in the server log for more detailed error messages.
NSM7222: Failed to configure. Check Server Log.
This error occurs if you stop the AppleTalk software, choose to notify VINES AFP users, and then try to restart the software immediately. To see if this is the case, select Display Port Status from the Main Menu. If the ports for the server still appear, it means that AppleTalk is still waiting for the one-minute notification period before it shuts down. Wait until the ports disappear from the Display Port Status screen before you attempt to restart AppleTalk.
VAN1801: Cannot start the AppleTalk software on the server
This error occurs if you try to start the AppleTalk software when the VINES Security Service is not running. Wait until the service is running, then try again.
This section gives suggestions for solving problems that users might have at their workstations.
User Cannot Access Server
Check that VINES AFP service is running. You can check this at the server console or at a workstation.
To check VINES AFP from the server console, at the Operator Menu, choose Display Service Status. To check VINES AFP from a workstation, you can use either OPERATE or MSERVICE.
To use OPERATE, follow these steps:
1. At the DOS or OS/2 prompt, type OPERATE and press RETURN. Use the arrow keys to select the server, and press RETURN.
2. Choose SELECT a Service to Operate. Press RETURN. Use the arrow keys to select the VINES AFP service. The Control a Service menu appears.
To use MSERVICE, follow these steps:
1. At the DOS or OS/2 prompt, type MSERVICE. From the Manage Services menu, choose SEARCH for Other Services.
2. From the Search For Services menu, choose Services on a Particular Server. Select the server the Macintosh user has trouble reaching.
3. From the Manage Services menu, use SELECT from List Below to select the VINES AFP service.
If you changed the network number range (Phase 2 networks) to a new range, reboot the Macintosh workstations on the affected LAN segment.
If the Macintosh workstation was started while not attached to the network, it is possible that the workstation has the same node address as another Macintosh workstation. Reboot the Macintosh workstation to make sure that it obtains a unique node address.
In a large network, a server between the user and the server that the user wants to reach might be down. Using a topology map and the TRACE a Route feature in VNSM, check to see if there are any network problems between the user' s server and the server that the user wants to reach. From the VINES Network Summary menu, choose TRACE a Route.
If the status indicates that the service is running, use VNSM to show the NBP (Name Binding Protocol) table.
To verify that the VINES AFP names are registered, follow these steps:
1. From the VINES Network Summary menu, choose SHOW protocol information. Press RETURN. Using the arrow keys, choose the server you want to check. Press RETURN.
2. From the Protocol Information menu, choose AppleTalk Names. Press RETURN.
3. On the Table data screen, look for the names of the VINES AFP service.
If you do not see VINES AFP listed, stop and restart the VINES AFP service.
If the status indicates that the service is down or stopped, restart it. From the Manage A Service menu, choose CONTROL the Service. Now choose START Service to restart it.
If the Macintosh workstation uses EtherTalk and the server's services do not appear at all, check to make sure that you have the correct version of EtherTalk on the Macintosh workstation. You can find these files in the System Folder. The phase of the EtherTalk driver on the workstations must match the phase which the server is running unless you use a transition bridge. (EtherTalk 1.0 supports Phase 1. EtherTalk 2.0 supports Phase 2.)
Zone Name Not in Chooser
Verify that the zone name has not been deleted.
If the zone name has been deleted intentionally, a new zone name might be available for users on that LAN segment. For example, in a large network, a network administrator may have deleted a zone called Mktg and replaced it with a new zone called ProdMktg. If this is the case, notify the user of the new zone name. If the zone name was deleted by accident, use Add a Zone to add the zone name to the LAN segment again.
Server Name Not in Chooser
If the server name does not show up in the Chooser on all the Macintosh workstations attached to that server:
Check the ports on the server using the Display Port Status screen. ("Displaying the Port Status" in Chapter 3 describes this procedure.) Check the status against the list of port status meanings in Table 3-8. Did the ports initialize properly? If no, stop AppleTalk. Wait until the port information has aged out (see "Verifying Age Out" in Chapter 3), then restart AppleTalk. If the ports did initialize properly, it is possible that the ports initialized too late for VINES AFP or the PostScript queues to register their names with these ports. Try stopping AppleTalk, waiting for all the ports to shut down, then restarting AppleTalk.
Stop and restart AppleTalk. Use the Display Port Status screen to watch the initialization process and to make sure that the ports initialize properly. It will take up to 5 minutes for the services to register their names again.
User Has Problems Logging On
If the Macintosh workstation user cannot log on,
Verify that AppleTalk is running. Verify that VINES AFP is running. Verify that the VINES AFP names are registered with the server using VNSM.
If the Macintosh workstation uses EtherTalk or TokenTalk and the server's services do not appear at all, check to make sure that you have the correct versions of EtherTalk or TokenTalk on the Macintosh workstation. You can find these files in the System Folder.
See the VINES User's Guide for Macintosh for information on troubleshooting the most common logon problems.
Duplicate Zone Names in the Chooser or in MNET.
This situation occurs when there are trailing spaces at the end of a zone name, in which case the zone name would be listed twice. For example, "TestZone" and "TestZone " would appear as two separate entries in the Chooser or in MNET, even though they are the same name. The trailing spaces at the end of the zone name are not obvious and therefore, it appears as though the zone name is duplicated or that there are two zones with an identical name.
To correct this problem, you must reconfigure the seed port with the incorrect zone name as follows:
1. Locate the router (seed port) configured with the duplicate name (with trailing spaces). You can use Apple's Interpoll Application to perform this procedure.
2. Stop AppleTalk on all routers which are members of this zone name.
Do not restart AppleTalk for at least 10 minutes. This allows the incorrect zone name to be purged from the memory of all the routers in the network.
3. Restart AppleTalk.
The problems listed in this section may appear at the server.
Network Number Wrong
If you are watching a port initialize using the Display Port Status screen, an unusual number may appear in this field. This is normal, and part of the initialization process. When the port is initializing, it uses a number in a preliminary startup range. It then probes to find an address in the real range. This initial number is what you see while the port is initializing.
Port Not Listed in Add a Port Menu
Use VNSM to verify that the LAN card is working.
When you rebooted the server, did VINES indicate that the LAN card was found? (As part of the reboot process, VINES lists each card in the server that it finds.) If not, make sure that you installed the card properly. Use ADD Cards/Change Card Configuration on the VINES Server Configuration menu to check the configuration for the card.
If you recently added the LAN card, did you remember to configure the card using ADD Cards/Change Card Configuration on the VINES Server Configuration menu? The AppleTalk configuration menus do not take the place of the Server Configuration menus.
If the card has not been configured, configure it now. If the card was configured, is the information correct? From the VINES Server Configuration menu, choose Add Cards/Change Card Configuration. Does the information on the screen match the way the card has been configured? Does it comply with the card manufacturer' s recommendations?
If the card was not recently added, did you use ADD Cards/Change Card Configuration on the VINES Server Configuration menu to change slot numbers? If you change the slot number, you must reconfigure the AppleTalk port associated with that slot number.
Part of Network is Unreachable
If part of the network is unreachable (the routes are not propagating), use the Display Routes screen to check the flags for the routes. ("Displaying AppleTalk Routes" in Chapter 3 describes this procedure.)
If bit 5 is set (which means that the server does not know the zone names for the destination network in the entry), the route will not be propagated. Look at the NxNt field for the network number of the next router. Look at the flags for that router to see what the problem is.
Check that there are no LAN segments with duplicate network numbers or overlapping network number ranges.
Tunneling Problems
Has someone disabled the VINES port? (If you disable the VINES port, you disable tunneling.) If the VINES port has been disabled, use ENABLE/DISABLE Port to re-enable the port.
Does the server you are trying to reach have restricted routing? If the server has restricted routing, you must add the names of any servers it can reach by using the ADD a Server menu. This procedure is described in "Adding a Server Entry" in Chapter 3.
Is the AppleTalk software loaded and running on the server you are trying to reach?
Does each configured VINES port have a unique network number?
To isolate tunneling problems, disable tunneling server by server by disabling the VINES port.
If tunneling is still not working, use the VNSM route tracing feature to see where the problem lies.
Zone Name Will Not Change
Has the zone name been changed recently? If you change a zone name, but the old zone name continues to exist in some parts of the network, it means that when the zone name was changed, the AppleTalk software was restarted before the old zone name aged out of the network.
To fix this problem, disable the port for 10 minutes (longer, if your network is exceptionally large), then enable it again. During the time that it is disabled, the old zone information should age out of the network. When you restart the network, the new zone name is propagated.
Use the following list for general troubleshooting, as an aid in finding nonspecific network problems.
Check the communication buffer percentage on the server. Configure a larger buffer size, if necessary.
The VNSM software provides valuable tools for finding network problems. For example, you can use VNSM to show communications statistics, protocol information, route information, and so on. Five of the VNSM menu choices relate to AppleTalk: AppleTalk Ports, AppleTalk Port Zones, AppleTalk Names, AppleTalk Zones, and AppleTalk Routes. Complete instructions for using these tools appears in Monitoring and Optimizing a VINES Network.Use the VNSM screens to check for dropped packets. VNSM displays the number of dropped packets for each AppleTalk protocol (for example, AARP, the AppleTalk Address Resolution Protocol). Dropped packets are packets that could not be received by the protocol due to insufficient server resources or bad headers in the packets. If dropped packets persist, consider increasing the communication buffer size from the server console. (See Monitoring and Optimizing Servers for information on using VNSM.)
To view protocol statistics, follow these steps:
1. From the Operator Menu, choose Run Network Management. Press RETURN.
2. Use the arrow keys to choose the server or servers you want to check from the list of available servers. Press F10. The VINES Network Summary menu appears. Choose SHOW Communications Statistics. Press RETURN.
3. Once again, use the arrow keys to select the server for which you want to show statistics. Press RETURN.
4. From the Communications Statistics menu, choose ACCESS Protocol Family Statistics. Press RETURN.
5. From the Protocol Families menu, choose APPLETALK Statistics. Press RETURN.
6. From the Family Summary menu, use the arrow keys to highlight the protocol for which you want to display statistics (for example, VINES AFP). Press RETURN.
Use the VNSM screens to display DDP statistics. DDP (the AppleTalk Datagram Delivery Protocol) is responsible for delivering unsequenced datagrams to destinations. Look at the statistics for the following fields:
Undel (Bad Dest) This indicates the number of times that a server attempted to route a DDP packet to a destination that has no entry in the server's AppleTalk routing table. Causes of this error include cable failures and router failures.
Wrong Length A significant number of wrong length errors can indicate packet corruption problems in the network. These problems can be caused by bad cables or router failures.
Hop Count Exceeded A hop count exceeded condition results from a poor network design or from a packet looping between routers. If poor network design is the problem, position routers in the network so that no route exceeds 15 hops.
Use the VNSM screens to display NBP statistics. NBP (the AppleTalk Name Binding Protocol) is responsible for resolving names of network entities, such as servers, file volumes and printers, and their network addresses. Look at the statistics for the following fields: Dropped, Bcast Requests Dropped, Lkup Requests Dropped, Lkup Replies Dropped, Fwd Requests Dropped. If these drops persist, consider increasing the size of the communication buffer on the server.
Use the VNSM screens to display RTMP statistics. RTMP (the AppleTalk Routing Table Maintenance Protocol) is responsible for building and updating routing tables on AppleTalk nodes. Look at the statistics for Dropped. If these drops persist, consider increasing the size of the communication buffer on the server.
Use the VNSM screens to display ZIP statistics. ZIP (the AppleTalk Zone Information Protocol) is responsible for mapping network numbers and zones in the network and for servicing requests from nodes for obtaining and changing the mapping. Look at the statistics for Drops. If these drops persist, consider increasing the size of the communication buffer on the server.
