diff --git a/DMRLookup.cpp b/DMRLookup.cpp
index 418c3e6..29aa66f 100644
--- a/DMRLookup.cpp
+++ b/DMRLookup.cpp
@@ -1,5 +1,5 @@
 /*
-*   Copyright (C) 2016 by Jonathan Naylor G4KLX
+*   Copyright (C) 2016,2017 by Jonathan Naylor G4KLX
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
@@ -103,6 +103,17 @@ std::string CDMRLookup::find(unsigned int id)
 	return callsign;
 }
 
+bool CDMRLookup::exists(unsigned int id)
+{
+	m_mutex.lock();
+
+	bool found = m_table.count(id) == 1U;
+
+	m_mutex.unlock();
+
+	return found;
+}
+
 bool CDMRLookup::load()
 {
 	FILE* fp = ::fopen(m_filename.c_str(), "rt");
diff --git a/DMRLookup.h b/DMRLookup.h
index 6cb3cda..ed09ac2 100644
--- a/DMRLookup.h
+++ b/DMRLookup.h
@@ -1,5 +1,5 @@
 /*
-*   Copyright (C) 2016 by Jonathan Naylor G4KLX
+*   Copyright (C) 2016,2017 by Jonathan Naylor G4KLX
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
@@ -36,6 +36,8 @@ public:
 
 	std::string find(unsigned int id);
 
+	bool exists(unsigned int id);
+
 	void stop();
 
 private:
diff --git a/P25Control.cpp b/P25Control.cpp
index 1fd6016..70707bc 100644
--- a/P25Control.cpp
+++ b/P25Control.cpp
@@ -179,7 +179,7 @@ bool CP25Control::writeModem(unsigned char* data, unsigned int len)
 	if (duid == P25_DUID_LDU1) {
 		if (m_rfState == RS_RF_LISTENING) {
 			m_rfData.reset();
-			bool ret = m_rfData.decodeLDU1(data + 2U, m_network != NULL, m_uidOverride);
+			bool ret = m_rfData.decodeLDU1(data + 2U);
 			if (!ret) {
 				m_lastDUID = duid;
 				return false;
@@ -189,28 +189,26 @@ bool CP25Control::writeModem(unsigned char* data, unsigned int len)
 
 			if (m_selfOnly) {
 				if (m_id > 99999999U) {		// Check that the Config DMR-ID is bigger than 8 digits
-					if (srcId != m_id / 100U) {
-						LogMessage("P25, invalid access attempt from %u", srcId);
-						m_rfState = RS_RF_REJECTED;
+					if (srcId != m_id / 100U)
 						return false;
-					}
 				}
 
 				else if (m_id > 9999999U) {	// Check that the Config DMR-ID is bigger than 7 digits
-					if (srcId != m_id / 10U) {
-						LogMessage("P25, invalid access attempt from %u", srcId);
-						m_rfState = RS_RF_REJECTED;
+					if (srcId != m_id / 10U)
 						return false;
-					}
 				}
 
 				else if (srcId != m_id) {	// All other cases
-					LogMessage("P25, invalid access attempt from %u", srcId);
-					m_rfState = RS_RF_REJECTED;
 					return false;
 				}
 			}
 
+			if (!m_uidOverride) {
+				bool found = m_lookup->exists(srcId);
+				if (!found)
+					return false;
+			}
+
 			bool           grp = m_rfData.getLCF() == P25_LCF_GROUP;
 			unsigned int dstId = m_rfData.getDstId();
 			std::string source = m_lookup->find(srcId);
@@ -321,9 +319,7 @@ bool CP25Control::writeModem(unsigned char* data, unsigned int len)
 			return true;
 		}
 	} else if (duid == P25_DUID_TERM || duid == P25_DUID_TERM_LC) {
-		if (m_rfState == RS_RF_REJECTED) {
-			m_rfState = RS_RF_LISTENING;
-		} else if (m_rfState == RS_RF_AUDIO) {
+		if (m_rfState == RS_RF_AUDIO) {
 			writeNetwork(m_rfLDU, m_lastDUID, true);
 
 			::memset(data + 2U, 0x00U, P25_TERM_FRAME_LENGTH_BYTES);
diff --git a/P25Data.cpp b/P25Data.cpp
index 11ec57c..3c9eb66 100644
--- a/P25Data.cpp
+++ b/P25Data.cpp
@@ -71,7 +71,7 @@ void CP25Data::encodeHeader(unsigned char* data)
 	CP25Utils::encode(DUMMY_HEADER, data, 114U, 780U);
 }
 
-bool CP25Data::decodeLDU1(const unsigned char* data, bool m_network, bool m_uidOverride)
+bool CP25Data::decodeLDU1(const unsigned char* data)
 {
 	assert(data != NULL);
 
@@ -105,12 +105,7 @@ bool CP25Data::decodeLDU1(const unsigned char* data, bool m_network, bool m_uidO
 		return false;
 	}
 
-		// Simple validation of the source id - does not check if no network
 	unsigned int srcId = (rs[6U] << 16) + (rs[7U] << 8) + rs[8U];
-	if (m_network || (!m_network && !m_uidOverride))  {
-		if (srcId < 1000000U)
-			return false;
-	}
 
 	switch (rs[0U]) {
 	case P25_LCF_GROUP:
diff --git a/P25Data.h b/P25Data.h
index dff5be0..6618da2 100644
--- a/P25Data.h
+++ b/P25Data.h
@@ -1,5 +1,5 @@
 /*
-*   Copyright (C) 2016 by Jonathan Naylor G4KLX
+*   Copyright (C) 2016,2017 by Jonathan Naylor G4KLX
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
@@ -28,7 +28,7 @@ public:
 
 	void encodeHeader(unsigned char* data);
 
-	bool decodeLDU1(const unsigned char* data, bool m_network, bool m_uidOverride);
+	bool decodeLDU1(const unsigned char* data);
 	void encodeLDU1(unsigned char* data);
 
 	void encodeLDU2(unsigned char* data);