dns cache beyond ttl - viasat / exede

Mon Oct 7 21:31:22 UTC 2019

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.