At first, a short introduction: Just joined the forum, after being a licensed user of PingPlotter since 2001. A really great tool, I need to consider buying another license just to give my tiny further support for the development work!
Then, to the actual issue. I found some previous posts about this, but decided to open a new one since the previous discussions were quite old.
Right now I'm monitoring a couple of problemful internet connections (kinda "dead ends", no humans or actual computers there but just some special hardware, like network cameras for surveillance). So, I need to do the monitoring from outside to that target, and the target is connected to the internet with lo-cost dsl line that has a dynamic ip address that gets updated to a dns server if the address changes.
I read those previous discussions about this, and noticed there are a couple of fundamental reasons why PingPlotter does not follow a changed ip address.
Of course, if there is a strict line "PingPlotter traces routes to ip addresses" there is not much more to say. However, I would find it very logical that if I specify a dns name to monitor, PingPlotter would really monitor route to an ip that is repeatedly resolved from that name. That is, if ip changes in dns, PingPlotter would turn to trace the new ip soon thereafter. Basically, the change could be noticed easily: dns information has expiration times, and if necessary, PingPlotter as a network tool could even have an option to bypass operating system's dns resolver and connect a specified dns server directly. In addition to dns expiration times possibly remembered by PingPlotter, an unreceived echo reply from the target could always be a reason to re-consult the dns server.
The second problem seemed to be related with "how to display this". IMHO, if following a trace to a target specified with name, I absolutely prefer not to drop old information or start a new trace if ip address changes, but just treat it in a similar way like any route change there may be on the way to the target. Then, ip change could simply be logged as a "route change", a feature that PingPlotter already has.
As a way to keep everybody happy, sometimes it might be necessary to concentrate to actual ip instead of the named target (though I guess then I would also specify the numeric ip, not a name). To overcome this, there could be a checkbox or configuration option to specify which behaviour is desired: to ask the dns information only at the very beginning, or repeat the dns query during the run.
I would appreciate this feature being looked at in the future development of PingPlotter.