I suppose they opt for really short TTLs for faster failover if needed?

toast0 · on July 29, 2022

Yeah, that's the idea, but then there's stuff like this:

   forums.adobe.com.       5       IN      CNAME   forum-redirects.trafficmanager.net.
   forum-redirects.trafficmanager.net.     60      IN      CNAME   encoderfuncus.azurewebsites.net.
   encoderfuncus.azurewebsites.net.        30      IN      CNAME   waws-prod-mwh-007.sip.azurewebsites.windows.net.
   waws-prod-mwh-007.sip.azurewebsites.windows.net.        1800    IN      CNAME   waws-prod-mwh-007.cloudapp.net.
   waws-prod-mwh-007.cloudapp.net. 60      IN      A       52.175.254.10

On a totally cold lookup, that takes at least 13 queries to load, because of the long CNAME chain, and azurewebsites.windows.net is sub-delegated with NS (with 5 minute ttl). That's a lot of back and forth to chase, and then much of it needs to be redone if someone comes back soon.