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Q: How can I troubleshoot problems when my Apple devices (iMac, PowerMac, Mac II, etc.) cannot access the network through my ProCurve Networking by HP switch?
This tech note is not intended to cover all possible issues in an ProCurve Networking by HP-Apple environment, but rather covers some specific layer 2 and 3 issues that are not documented well elsewhere. For example, router configuration issues and node address management are not covered here as those topics are thoroughly documented in various Web pages, manuals, and textbooks.
A: First, you should try to distinguish between Ethernet problems and higher network layer (that is, IP or AppleTalk) problems.
To verify Ethernet connectivity:
- Inspect the switch Link LED (do you have link?). If not, verify that the port configurations (Auto versus 10Mbps fixed versus 100Mbps fixed) on the switch and Apple device are compatible. If auto-negotiation does not work, try setting both the switch and Apple device to the same speed and mode (that is: full duplex versus half duplex).
- Check the port status display (if an ProCurve Networking by HP switch) or show interface command (if an ProCurve Networking by HP Routing Switch). Is the port up? Is it operating at the correct speed and mode?
- Check the ProCurve Networking by HP switch event log for warnings (that is, look for a "W" as the first character in the event log messages) that might explain the connectivity issue. For example, Fault Finder Indications (FFI) on the affected client's or server's port would lead you to suspect an Ethernet-level issue.
- Look at the port counters for presence or absence of Ethernet link and Ethernet errors. If you are unsure how to interpret the errors, see the ProCurve Networking by HP Information Library article: troubleshooting LAN performance and intermittent connectivity problems.
If the switch or routing switch reports that you have link and that packets are going in both directions between the switch or routing switch and the Apple device without errors, then you probably are not having Ethernet-level (that is: OSI layer 2) problems between the switch and the Apple device.
You can perform additional Ethernet and IP connectivity end-to-end testing by using a 3rd party ping utility such as one of the following:
- MacPing (by Dartware, LLC)
- Mac TCP Watcher (by Stairways Software)
- Mac TCP Ping (Apple Computer, Inc.)
Hewlett-Packard has not evaluated these software applications, does not make any claims regarding their appropriateness, and does not support them.
Using ping, you can test connectivity along the entire path between the client and server. If ping succeeds, but AppleTalk communication (such as Chooser finding services) fails, that indicates an AppleTalk-specific issue, as opposed to an Ethernet-level connectivity issue.
If the switch information and your ping attempts indicate that the Ethernet connections and IP connectivity are sound, you should move on to troubleshoot at the AppleTalk or IP layer. Note: even if you have configured an IP address on your Mac and intend to use IP (not AppleTalk), the Mac computers still use AppleTalk for certain functions. The Chooser, for example, relies on AppleTalk.
One of the most common symptoms is that one or more Macs cannot see any (or all) AppleTalk zones or cannot see any other Apple devices on the LAN. Bear in mind that there can be many root causes for this symptom. Several of them are described in Apple Computer, Inc's support database. For example, Article ID 30841 iMac and Power Macintosh G3: Not Seeing AppleTalk Zones or Devices on Ethernet describes an issue that can be resolved by clearing the Mac's factory-default Preferences. Article ID 24577 AppleShare IP 6.0: Troubleshooting Network Connectivity also discusses various remedies for an inability to see zones. If your Mac's Chooser can only see other Apple devices that are in its zone, note that this is correct behavior. According to Inside AppleTalk (by Sidhu, Andrews, and Oppenheimer), a particular Apple end node belongs to only one zone and can only learn of other printers and servers on other zones through GetZoneList or GetLocalZone transactions with an AppleTalk router.
If your Mac computer shows nothing in the Chooser, make sure that the AppleTalk Control Panel has the right connection type, for example: Ethernet. Also, try deactivating and reactivating AppleTalk.
In general, you can have up to 254 Apple devices on a cable range (that is, network number) without a router. In some cases, however, the amount of multicast AppleTalk traffic may result in issues with only a few dozen AppleTalk nodes in a switched LAN. In addition, each zone has a multicast address associated with it. A zone that is too large may result in too much zone-related traffic.
If the amount of AppleTalk multicast and broadcast traffic on your network is affecting your nodes' ability to communicate, you may need to divide your network into cable ranges (networks) and/or zones and install a device that acts as an AppleTalk router. Doing so will reduce the amount of multicast AppleTalk traffic that each AppleTalk client, server, or printer has to process.
If you are using Apple Computer's Open Transport, verify that you have the latest version installed or have checked the Read Me files for versions newer than the one you are using. Recent versions of Open Transport have fixed certain communications issues.
If you have moved the Mac from one network to another, parameter memory (PRAM) may contain IP or AppleTalk network settings that are incompatible with the new location. You may need to clear PRAM in order for the Mac to work on its new network.
Glossary of terms
AppleShare - The file service portion of the AppleTalk protocol stack.
AppleTalk - The higher level (that is, above Ethernet and LocalTalk) network protocol stack for Apple clients, servers, and printers. AppleTalk may run on Ethernet or LocalTalk.
Cable range - A range of AppleTalk network numbers. Apple networking literature variously refers to "network numbers" and "cable ranges". These terms mean the same thing.
EtherTalk - AppleTalk protocol running on Ethernet.
LocalTalk - Both: 1) a layer 1 and 2 cabling system developed by Apple Computer, Inc. that runs at 230kbps; and 2) the AppleTalk protocol stack running on LocalTalk cabling.
Zone - An arbitrary subset of those AppleTalk devices on an internetwork. Each AppleTalk end node belongs to only one zone.
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