By storing previous DNS query answers of name:ip mappings in a local cache, system responsiveness will be greatly enhanced.  This link is a HowTo I've written which details how to configure "systemd-resolved" as a local dual IPv4/IPv6 DNS caching stub resolver.

 

What little documentation I could find on the subject sparse and confusing as it could vary by both the version of systemd AND the distro it was being configured on.  So I wrote a HowTo on StackExchange for Raspbian which can be found at the below link:

https://raspberrypi.stackexchange.com/questions/96763/configure-caching-ipv4-ipv6-dns-stub-resolver-using-systemd-resolv…

 

Hope this saves others wasted time & confusion- Terrence