4 ms·

Yes, for 40 minutes to 1 hour. But I bet you still ran forwarders on the old hosts for at least an hour after you cut over DNS.

• yjftsjthsd-h 6y ago
  > But I bet you still ran forwarders on the old hosts for at least an hour after you cut over DNS. I promise you we did not.
  • stevekemp 6y ago
    That's a surprise - I've handled migrations like this in the past, and we always setup a simple proxy to forward traffic for a while. I've definitely lost count of the number of clients that would cache the old IPs, despite valid and low TTLs being in-place well in advance of a migration.
    • yjftsjthsd-h 6y ago
      The impression I got from the senior sysadmins was that we considered clients caching records beyond TTL to be a bug on their side and not our problem, and (importantly) the nature of our business/clients allowed us to make that determination and not take corrective measures to compensate for client-side misconfigurations. As such, practicing traffic would have been considered at best unnecessary work (and at worst comprising our testing process and encouraging bad behavior).
      • stevekemp 6y ago
        I can appreciate that, I know that I would see traffic hit the old IP for >3 days. I suspect old Java clients, etc, that would resolve IPs once on startup and never again. In our case it was worth keeping things working for a few days, but after a week at the outside we'd kill the proxying/forwarding.
  • ikiris 6y ago
    There were major providers that at one point in time overrode TTLs to a minimum week if under 24h.