MacPing tests how well your AppleTalk or IP (Internet Protocol) network carries data packets. It supports a variety of probe types including AppleTalk Echoes, Name-Binding Probes, ICMP Echoes, and SNMP.
This document contains information that didn't make it into the manual in time. It describes some situations where MacPing may appear to work strangely.
Please send questions or comments to "MacPing@Dartmouth.EDU".
Known Problems with MacPing™ 3.0.4
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• When connected to an ARA 2.0 server using Open Transport 1.1, AppleTalk addresses are different each time you refresh the device list.
Release Notes for MacPing™ 3.0.4
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• All networking code is native for Open Transport.
Release Notes for MacPing™ 3.0.3
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• Fixed a minor bug in copying or saving IP device names which exceed 32 characters in length.
• Worked around a problem with early versions of Open Transport and HINFO queries.
• Made it possible for MacPing to be localized for different languages.
Release Notes for MacPing™ 3.0.2
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• When saving IP host information to a TEXT file (or when copying the information to the clipboard), MacPing 3.0.1 would insert the current AppleTalk zone name as part of the text. This has been fixed.
Release Notes for MacPing™ 3.0.1
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MacPing 3.0.1 has an improved user interface over that documented in the printed manual.
• Color! MacPing sports a gray background on color monitors. The traces also use color, with green for valid replies and red for drops.
• Devices with multiple names include a downward triangle to the right of the name.
• There are menu commands for zeroing the percent dropped and resetting the minimum and maximum response times.
• MacPing does not automatically open MacTCP at start-up.
• When saving information to a file, MacPing includes a column with the zone name for each device. MacPing also includes the zone name when copying selected device information to the clipboard.
• MacPing supports two new AppleScript commands: the “Pause” command stops testing. The “Resume” command resumes testing.
Release Notes for MacPing™ 3.0
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The symptoms addressed below only affect specific network environments. You should definitely read further if you use MacPing 3.0 over Apple Remote Access (ARA), with MacTCP 1.1.1, or with extended networks that have multiple zones.
WHAT: While testing LaserWriters in Automatic mode, MacPing increases its timeout to 2500 msec.
WHY: During printing, LaserWriters take a long time respond to Printer Status packets. This delay can be as long as 2500 msec (2.5 seconds). If the timeout is set too short, MacPing will decide (incorrectly) that the packet was lost.
SOLUTION: Test LaserWriters in Automatic Timer mode. To do this, choose Adjust Timers from the MacPing menu, and check the Automatic checkbox. MacPing will automatically use the longer timeout for LaserWriters.
WHAT: The "Scour AppleTalk Network" command may crash certain AppleTalk/IP routers.
WHY: The "Scour AppleTalk Network" command works by sending a single Name-Binding Probe to each of the legal node numbers in a network that are not already in the device list. If the target network is Ethernet, its router will be forced to send AARP packets for nodes which may not exist. Even though MacPing sends out the Name-Binding probes relatively slowly, the previous AARPing may still be going on when the router receives the next probe. Certain AppleTalk/IP routers will crash if the maximum number of concurrent AARP's is exceeded.
SOLUTION: Only use the "Scour AppleTalk Network" command when you believe MacPing may have missed some responses because of a flood of replies. Be careful about using it for Ethernet networks—it's probably unnecessary.
WHAT: When testing a single network with multiple zones, devices in other zones (but with the same network number) may still show up in the device list. This happens if you are testing all nets in zone and then choose a specific network from the network pop-up menu.
WHY: The "extra" nodes show up because MacPing broadcasts an echo packet to find extra devices that it missed with NBP. MacPing then looks up the names of the unknown devices that gave echo replies. It is not always possible to tell which zone a device is in, so MacPing errs on the side of showing more devices than it really should. If you only want to test devices in a specific zone, choose "All Nets In Zone".
Over ARA, MacPing has a slightly different behavior. Devices in other zones may show up as "Unknown" devices. MacPing can't get the names because ARA manipulates Name-Binding packets.
SOLUTION: If you are unsure whether a particular network number has multiple zones, use the "Test Network..." dialog to enter the network number. The Zone: popup menu will tell you whether there is more than one zone for that network. If you want to test devices in a specific zone, select the "All Nets In Zone" option from the Network pop-up.
WHAT: MacPing may hang when sending Long ICMP Echoes, via MacIP, over an ARA link.
WHY: Long ICMP Echo packets contain 1500 bytes, which is longer than the maximum AppleTalk packet length. Consequently, these long packets must be broken into fragments, and sent as several AppleTalk packets. MacTCP appears to have a problem when sending many fragmented ICMP echoes over a slow link. This trouble occurs more often if MacPing's timeout is set low.
SOLUTION: There is no workaround for this. Avoid using Long ICMP echoes over ARA.
WHAT: Can't ping the Macintosh's own IP address with ICMP echoes.
WHY: This is a minor bug in MacTCP that only occurs with a direct Ethernet connection. (Note: With MacIP addressing, you can ping yourself but you are actually testing the round-trip path twice: the request goes to the gateway and comes back, and then the reply goes to the gateway and comes back.)
SOLUTION: There is no workaround for this problem. On the other hand, it's certain that the Mac's connection "through the network to itself" is working if other devices ping properly.
