On 10/7/19 9:08 AM, Mike wrote:
I am wondering if perhaps this is due to some kind of (known?) bug in the embedded dns cache/client in the client satellite modem, or if there is another plausible explanation I am not seeing. It compounds my problem slightly since I have to continue running the web sites at both the old and new addresses while these things time out I guess and it's just inconvenient.
Back when I was the mail/DNS/network admin at a hosting company, and we would have to renumber, I saw the same thing. This was back in the days when the cable companies had small pipes to the Internet. Their DNS servers would impose a minimum 1 week TTL on all DNS requests, so that the vast majority would be resolved "locally" without having to resort to the root servers. Other answers point to satellite companies doing something similar, to combat the long RTD that DNS resolution would require without aggressive caching. Almost all of the Web servers I managed used Linux, so I was able to play games in the firewall to let both numbers get to the Web servers without having a convoluted configuration in Apache. The three Windows/ISS hosts were not that difficult to do, but was tiresome. Those games stopped when the hosting company got its own /21 allocation.