Diagnosing Network Problems Using PingPlotter

Many network problems, given enough test cases, can be diagnosd by simple observation and comparison. If you can access Computer C from Computers A and B, but you can't from Computer D, better look at Computer D. If Computer A can access Websites 1 and 2, but can't access Website 3, what's different about Website 3?

What if the problem comes and goes - now you can access with no problem, and now you can't? Maybe Computer A doesn't work now, but it's working later when Computer B stops working? Or if Website 1 is accessible, but Website 2 isn't, how do you identify the problem?

I start with PingPlotter. PingPlotter combines a traceroute (traditionally a single timed ping of all addressed hosts between one computer and another) with repetitious pinging, and an interactive GUI display. PingPlotter lets you look for geographical problems (showing that you have connectivity between your computer and the first router, but not the second), or for repetitous problems (showing when you lose connectivity, whether chronic, cyclical, or randomly).

Let's say that you are losing connection with the Internet, on all computers on your LAN, periodically. By running PingPlotter on your computers, you can note whether the problem is with your router (if all computers show loss of connectivity with that router), with your ISP (if all computers show loss of connectivity with your ISPs gateway, but no problem with your router), or with a given server on the Internet. If the problem is intermittent, the PingPlotter display will show when the problem happens - and if its a chronic problem which includes loss of connectivity with your ISP, having a PingPlotter display may be worth a thousand words.

Since PingPlotter shows ping times for every host between you and your target, when there is a break in connectivity somewhere, it will show the break. You will see a red ping display for any hosts that do not respond at all, and the host that is causing the problem should be the first one showing as red.

A PingPlotter display is interactive too. If there are a dozen hosts between you and a given website, maybe you only want to examine connectivity details with 4 hosts - yours, your ISPs gateway, your ISPs border, and the target server. You can selectively configure PingPlotter to show only those hosts, saving valuable screen space for other tasks. At any time, you can add any of the other hosts to the display, and the past history for those hosts will be visible too.

You can also vary the time scope of the display. You can look at an entire 48 hours in a 6 inch horizontal display, or zoom in on any 5 minutes, and look at those 5 minutes in detail. Or you can select any of 8 other scales in the display.

The paid version of PingPlotter can even be set to trigger alerts when certain definable network conditions occur, and to contact you by text messaging, or by email. So you need not be at your desk, watching the display, to be notified of a chronic problem.

All in all, PingPlotter is one network diagnostic that has a place in my toolbox. The paid version, PingPlotter Pro, is well worth the expense.