Minimal DNS forwarder with blacklist support.
Minimal, this utility does not implement caching, DoT, DoH or DNSSEC. There are software packages that can do that already and can do that better, check them all.
go get -u github.com/foxcpp/rhole
rhole /etc/rhole.toml
rhole.toml example:
listen = "127.0.0.1:53"
downstreams = ["1.1.1.1", "9.9.9.10"]
blacklists = ["/etc/bad_domains"]
Btw, ρ (rho) is the next Greek letter after pi. pi-hole is nice too.