Hi, I have recently started using Knot Resolver. Thanks for that really nice piece of software. Knot Resolver seems to cache the TTL of parent zone (= delegation) instead of the TTL which is in the zone itself. dig +noall +auth @n.ns.at univie.ac.at ns univie.ac.at. 10800 IN NS ns3.univie.ac.at. univie.ac.at. 10800 IN NS ns4.univie.ac.at. univie.ac.at. 10800 IN NS ns5.univie.ac.at. univie.ac.at. 10800 IN NS ns7.univie.ac.at. univie.ac.at. 10800 IN NS ns8.univie.ac.at. univie.ac.at. 10800 IN NS ns10.univie.ac.at. dig +noall +ans @ns10.univie.ac.at univie.ac.at ns univie.ac.at. 600 IN NS ns7.univie.ac.at. univie.ac.at. 600 IN NS ns4.univie.ac.at. univie.ac.at. 600 IN NS ns8.univie.ac.at. univie.ac.at. 600 IN NS ns3.univie.ac.at. univie.ac.at. 600 IN NS ns5.univie.ac.at. univie.ac.at. 600 IN NS ns10.univie.ac.at. dig +noall +ans @ns10.univie.ac.at ns10.univie.ac.at a ns10.univie.ac.at. 600 IN A 192.76.243.2 Knot Resolver is caching 10800 instead of 600: dig +noall +answer @127.0.0.1 ns10.univie.ac.at a ns10.univie.ac.at. 10634 IN A 192.76.243.2 Bind, unbound and pdns-recursor cache authoritative TTL (600). I have tried to file a bug report at https://gitlab.labs.nic.cz/labs/knot/issues , but I wasn't able to create a user account. cheers, -arsen