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To isolate and resolve AppleTalk problems, complete the following steps:
Use an Echo test to determine whether the router can communicate with a particular node on one of its networks.
When you execute an Echo test, the router sends a specified number of packets across the network to a specified node; the node then returns the same number of packets.
If the Number of Packets Received field does not increment, the specified node might be switched off or a cable connection might have become loose.
If an Echo test executes successfully, the number of packets received is equal or nearly equal to the number of packets sent. If the communication is successful, AppleTalk is working on that interface and the specified node is up and running.
To execute an Echo test:
Select Lookup Network Entities from the Available Actions window of ATCON.
Enter a zone name in the Name field.
Select Perform Lookup for the Proceed option.
Select an entity from the displayed list.
Edit the following test parameters as required: Mode, Number of Packets to Send, Timeout, and Number of Data Bytes.
Use an Echo test to determine whether the router can communicate with a node on a remote AppleTalk network.
Use the same procedure described in Step 1 .
If the test is successful, the router can reach another AppleTalk network, and all intermediate AppleTalk routers are routing correctly.
If the test is not successful, execute an Echo test to the closest router on the path to the remote node. Continue Echo testing each router along the path until you find the closest point at which the test fails, then perform corrective action on the router that failed. Check the interfaces in ATCON and enter CONFIG at the system console prompt to determine whether the interface has a hardware problem. Verify that AppleTalk is bound to the network interface with the correct address.
Check the routing table in ATCON.
The Routing Table option contains entries for all networks and zones to which the router can send packets. If entries are missing, verify that each router on the internetwork is active and advertising routes. Check for any filters that would interfere with the propagation of routes.
Check the zones list in ATCON.
The Zones List option displays a global list of all AppleTalk zones in the internetwork. This list should be identical to the zones list that appears in the Macintosh Chooser. If entries are missing, verify that each router on the internetwork is active. Check for any filters that would interfere with the propagation of zones.
Verify that AppleTalk is bound to the interface.
Use ATCON to check the system log file for error messages.
The No Route Found statistic indicates that entries are missing from the routing table. The Too Many Hops statistic indicates that the path between some nodes in your internetwork is too long.
Verify that the AppleTalk configuration options in NIASCFG are set to the proper values.
Check the AppleTalk Packet Statistics option in ATCON.
If you find Bad DDP Length errors, you probably have a malfunctioning interface board or an incorrect version of the board driver software.
If you find Bad DDP Checksum errors, use the LANalyzer® software to find the device that is sending packets with bad checksums.
If you find No Route Found errors, there is probably a malfunctioning router or a malfunctioning cable between your router and the destination. To find the portion of the network with the problem, follow the route and send NBP lookups or echo packets to each router along the way until you find a router that knows the route to the final destination. The problem is located between the router that knows the route and the previous router in the path.
If you find Too Many Hops errors, verify that no clients are more than 15 hops away from the servers they access.
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