diff --git a/src/network/core/tcp_stun.cpp b/src/network/core/tcp_stun.cpp
new file mode 100644
--- /dev/null
+++ b/src/network/core/tcp_stun.cpp
@@ -0,0 +1,29 @@
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+ * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * @file tcp_stun.cpp Basic functions to receive and send STUN packets.
+ */
+
+#include "../../stdafx.h"
+#include "../../debug.h"
+#include "tcp_stun.h"
+
+#include "../../safeguards.h"
+
+/**
+ * Helper for logging receiving invalid packets.
+ * @param type The received packet type.
+ * @return Always false, as it's an error.
+ */
+bool NetworkStunSocketHandler::ReceiveInvalidPacket(PacketStunType type)
+{
+	Debug(net, 0, "[tcp/stun] Received illegal packet type {}", type);
+	return false;
+}
+
+bool NetworkStunSocketHandler::Receive_SERCLI_STUN(Packet *p) { return this->ReceiveInvalidPacket(PACKET_STUN_SERCLI_STUN); }