diff --git a/internal/cmd/oohelperd/internal/webconnectivity/dns.go b/internal/cmd/oohelperd/internal/webconnectivity/dns.go
index 5808111..221774a 100644
--- a/internal/cmd/oohelperd/internal/webconnectivity/dns.go
+++ b/internal/cmd/oohelperd/internal/webconnectivity/dns.go
@@ -28,5 +28,8 @@ type DNSConfig struct {
 func DNSDo(ctx context.Context, config *DNSConfig) {
 	defer config.Wg.Done()
 	addrs, err := config.Resolver.LookupHost(ctx, config.Domain)
+	if addrs == nil {
+		addrs = []string{} // fix: the old test helper did that
+	}
 	config.Out <- CtrlDNSResult{Failure: newfailure(err), Addrs: addrs}
 }
diff --git a/internal/cmd/oohelperd/internal/webconnectivity/http.go b/internal/cmd/oohelperd/internal/webconnectivity/http.go
index 673c6e2..5fd2bd5 100644
--- a/internal/cmd/oohelperd/internal/webconnectivity/http.go
+++ b/internal/cmd/oohelperd/internal/webconnectivity/http.go
@@ -30,7 +30,11 @@ func HTTPDo(ctx context.Context, config *HTTPConfig) {
 	defer config.Wg.Done()
 	req, err := http.NewRequestWithContext(ctx, "GET", config.URL, nil)
 	if err != nil {
-		config.Out <- CtrlHTTPResponse{Failure: newfailure(err)}
+		config.Out <- CtrlHTTPResponse{ // fix: emit -1 like the old test helper does
+			BodyLength: -1,
+			Failure:    newfailure(err),
+			StatusCode: -1,
+		}
 		return
 	}
 	// The original test helper failed with extra headers while here
@@ -45,7 +49,11 @@ func HTTPDo(ctx context.Context, config *HTTPConfig) {
 	}
 	resp, err := config.Client.Do(req)
 	if err != nil {
-		config.Out <- CtrlHTTPResponse{Failure: newfailure(err)}
+		config.Out <- CtrlHTTPResponse{ // fix: emit -1 like old test helper does
+			BodyLength: -1,
+			Failure:    newfailure(err),
+			StatusCode: -1,
+		}
 		return
 	}
 	defer resp.Body.Close()
diff --git a/internal/cmd/oohelperd/oohelperd.go b/internal/cmd/oohelperd/oohelperd.go
index 189b007..e582962 100644
--- a/internal/cmd/oohelperd/oohelperd.go
+++ b/internal/cmd/oohelperd/oohelperd.go
@@ -12,6 +12,7 @@ import (
 	"github.com/ooni/probe-cli/v3/internal/cmd/oohelperd/internal/webconnectivity"
 	"github.com/ooni/probe-cli/v3/internal/cmd/oohelperd/internal/websteps"
 	"github.com/ooni/probe-cli/v3/internal/engine/netx"
+	"github.com/ooni/probe-cli/v3/internal/runtimex"
 )
 
 const maxAcceptableBody = 1 << 24
@@ -31,7 +32,10 @@ func init() {
 	dialer = netx.NewDialer(netx.Config{Logger: log.Log})
 	txp := netx.NewHTTPTransport(netx.Config{Logger: log.Log})
 	httpx = &http.Client{Transport: txp}
-	resolver = netx.NewResolver(netx.Config{Logger: log.Log})
+	// fix: use 8.8.8.8:53/udp so we pin to a specific resolver.
+	var err error
+	resolver, err = netx.NewDNSClient(netx.Config{Logger: log.Log}, "udp://8.8.8.8:53")
+	runtimex.PanicOnError(err, "NewDNSClient failed")
 }
 
 func shutdown(srv *http.Server) {