Index: Datagrams.cpp
===================================================================
--- Datagrams.cpp	(revision 5371)
+++ Datagrams.cpp	(working copy)
@@ -1365,6 +1365,18 @@
 		return FALSE;
 	}
 
+	if ( ! (pHits->m_pAddress.S_un.S_un_b.s_b1 == pHost->sin_addr.S_un.S_un_b.s_b1 &&
+		    pHits->m_pAddress.S_un.S_un_b.s_b2 == pHost->sin_addr.S_un.S_un_b.s_b2 &&
+		    pHits->m_pAddress.S_un.S_un_b.s_b3 == pHost->sin_addr.S_un.S_un_b.s_b3 &&
+		    pHits->m_pAddress.S_un.S_un_b.s_b4 == pHost->sin_addr.S_un.S_un_b.s_b4 ) )
+	{
+		pPacket->Debug( _T("UDP Sender IP does not match packet NA") );
+		theApp.Message( MSG_ERROR, IDS_PROTOCOL_BAD_HIT,
+			(LPCTSTR)CString( inet_ntoa( pHost->sin_addr ) ) );
+		Statistics.Current.Gnutella2.Dropped++;
+		return FALSE;
+	}
+
 	if ( Security.IsDenied( &pHits->m_pAddress ) || nHops > (int)Settings.Gnutella1.MaximumTTL )
 	{
 		pHits->Delete();