For a long time I've had ipv6 disabled on all systems here. :)

Were you thinking ipv6 was the cause of not getting through to the VOIP router?

Hmm. Curiouser and curiouser as Alice would say.

Just now I performed some maintenance on the laptop and connected to my network with the cable. I disabled the wireless switch before powering on the laptop. The maintenance required extensive file transfers and they worked great. A few moments later and I was unable to access the internet, as I reported in comment 29. That is, I can ping my local router but can't ping the VOIP router. I had my main office machine on at the same time and that system could ping the VOIP router.

The file transfers all were local (not internet). I did not look or notice as to whether I could ping the VOIP router before I noticed the failure. That is, the failure could have existed all along but the local file transfers would not expose the problem.

I think I'll a ping test to my rc.local.

Something strange is happening here. :)