Add the repo
echo "deb [signed-by=/etc/apt/keyrings/dnsdist-18-pub.asc arch=amd64] http://repo.powerdns.com/debian bookworm-dnsdist-18 main" > /etc/apt/sources.list.d/dnsdist.list
Tell apt to prefer dnsdist from the PDNS repo
echo "Package: dnsdist*
Pin: origin repo.powerdns.com
Pin-Priority: 600" > /etc/apt/preferences.d/dnsdist-18
Install the repo key
install -d /etc/apt/keyrings; curl https://repo.powerdns.com/FD380FBB-pub.asc | tee /etc/apt/keyrings/dnsdist-18-pub.asc
Install dnsdist
apt update
apt install dnsdist