dnsdist.lua

-- Define backend pools
newServer{address="tls://8.8.8.8", pool="google", tlsHostname="dns.google"}
newServer{address="tls://8.8.4.4", pool="google", tlsHostname="dns.google"}

newServer{address="tls://1.1.1.1", pool="cloudflare", tlsHostname="cloudflare-dns.com"}
newServer{address="tls://1.0.0.1", pool="cloudflare", tlsHostname="cloudflare-dns.com"}

-- Define local listeners
addLocal("127.0.0.1:5301", {pool="google"})
addLocal("127.0.0.1:5302", {pool="cloudflare"})
addLocal("0.0.0.0:53")  -- Main listener

-- Main listener will round-robin to both upstream pools via custom routing
function mainRouter(dq)
    -- Round-robin or custom logic
    if math.random() < 0.5 then
        dq:setPool("google")
    else
        dq:setPool("cloudflare")
    end
    return DNSAction.None
end

setServerPolicy("leastOutstanding") -- or "firstAvailable", "roundrobin", etc.