diff --git a/webrtc/p2p/client/basicportallocator.cc b/webrtc/p2p/client/basicportallocator.cc
index 5c322da59e..41edd85e9e 100644
--- a/webrtc/p2p/client/basicportallocator.cc
+++ b/webrtc/p2p/client/basicportallocator.cc
@@ -412,11 +412,6 @@ void BasicPortAllocatorSession::DoAllocate() {
         break;
       }
 
-      // Disables phases that are not specified in this config.
-      if (!config || config->StunServers().empty()) {
-        // No STUN ports specified in this config.
-        sequence_flags |= PORTALLOCATOR_DISABLE_STUN;
-      }
       if (!config || config->relays.empty()) {
         // No relay ports specified in this config.
         sequence_flags |= PORTALLOCATOR_DISABLE_RELAY;
@@ -980,9 +975,6 @@ void AllocationSequence::CreateStunPorts() {
     return;
   }
 
-  // If BasicPortAllocatorSession::OnAllocate left STUN ports enabled then we
-  // ought to have an address for them here.
-  ASSERT(config_ && !config_->StunServers().empty());
   if (!(config_ && !config_->StunServers().empty())) {
     LOG(LS_WARNING)
         << "AllocationSequence: No STUN server configured, skipping.";
diff --git a/webrtc/p2p/client/portallocator_unittest.cc b/webrtc/p2p/client/portallocator_unittest.cc
index 0173261f37..148623dfb3 100644
--- a/webrtc/p2p/client/portallocator_unittest.cc
+++ b/webrtc/p2p/client/portallocator_unittest.cc
@@ -116,7 +116,9 @@ class PortAllocatorTest : public testing::Test, public sigslot::has_slots<> {
         rtc::NAT_OPEN_CONE, vss_.get(), kNatAddr, vss_.get(), kNatAddr));
 
     ServerAddresses stun_servers;
-    stun_servers.insert(stun_server);
+    if (!stun_server.IsNil()) {
+      stun_servers.insert(stun_server);
+    }
     allocator_.reset(new cricket::BasicPortAllocator(
         &network_manager_, &nat_socket_factory_, stun_servers));
     allocator().set_step_delay(cricket::kMinimumStepDelay);
@@ -873,7 +875,8 @@ TEST_F(PortAllocatorTest, TestSharedSocketWithNatUsingTurn) {
 // 'relay' candidates.
 TEST_F(PortAllocatorTest, TestSharedSocketWithNatUsingTurnAsStun) {
   AddInterface(kClientAddr);
-  ResetWithNatServer(kTurnUdpIntAddr);
+  // Use an empty SocketAddress to add a NAT without STUN server.
+  ResetWithNatServer(SocketAddress());
   AddTurnServers(kTurnUdpIntAddr, rtc::SocketAddress());
 
   // Must set the step delay to 0 to make sure the relay allocation phase is