DNS: add test to verify NXDOMAIN is returned when a non-existent domain is queried over RPC

agent/dns_test.go

@@ -5790,15 +5790,17 @@ func TestDNS_AddressLookupIPV6(t *testing.T) {
 	}
 }
 
-func TestDNS_NonExistingDC(t *testing.T) {
+// TestDNS_NonExistentDC_Server verifies NXDOMAIN is returned when
+// Consul server agent is queried for a service in a non-existent
+// domain.
+func TestDNS_NonExistentDC_Server(t *testing.T) {
 	t.Parallel()
 	a := NewTestAgent(t, "")
 	defer a.Shutdown()
 	testrpc.WaitForLeader(t, a.RPC, "dc1")
 
-	// lookup a non-existing node, we should receive a SOA
 	m := new(dns.Msg)
-	m.SetQuestion("consul.dc2.consul.", dns.TypeANY)
+	m.SetQuestion("consul.service.dc2.consul.", dns.TypeANY)
 
 	c := new(dns.Client)
 	in, _, err := c.Exchange(m, a.DNSAddr())
@@ -5811,6 +5813,47 @@ func TestDNS_NonExistingDC(t *testing.T) {
 	}
 }
 
+// TestDNS_NonExistentDC_RPC verifies NXDOMAIN is returned when
+// Consul server agent is queried over RPC by a non-server agent
+// for a service in a non-existent domain
+func TestDNS_NonExistentDC_RPC(t *testing.T) {
+	t.Parallel()
+	s := NewTestAgent(t, `
+		node_name = "test-server"
+	`)
+
+	defer s.Shutdown()
+	c := NewTestAgent(t, `
+		node_name = "test-client"
+		bootstrap = false
+		server = false
+	`)
+	defer c.Shutdown()
+	testrpc.WaitForLeader(t, s.RPC, "dc1")
+
+	// Join LAN cluster
+	addr := fmt.Sprintf("127.0.0.1:%d", s.Config.SerfPortLAN)
+	_, err := c.JoinLAN([]string{addr})
+	require.NoError(t, err)
+	retry.Run(t, func(r *retry.R) {
+		require.Len(r, s.LANMembers(), 2)
+		require.Len(r, c.LANMembers(), 2)
+	})
+
+	m := new(dns.Msg)
+	m.SetQuestion("consul.service.dc2.consul.", dns.TypeANY)
+
+	d := new(dns.Client)
+	in, _, err := d.Exchange(m, c.DNSAddr())
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	if in.Rcode != dns.RcodeNameError {
+		t.Fatalf("Expected RCode: %#v, had: %#v", dns.RcodeNameError, in.Rcode)
+	}
+}
+
 func TestDNS_NonExistingLookup(t *testing.T) {
 	t.Parallel()
 	a := NewTestAgent(t, "")