diff --git a/src/i_net.cpp b/src/i_net.cpp
index 2c01f407d..889688b48 100644
--- a/src/i_net.cpp
+++ b/src/i_net.cpp
@@ -293,7 +293,7 @@ void PacketGet (void)
 			return;
 		}
 	}
-	else if (c > 0)
+	else if (node >= 0 && c > 0)
 	{
 		doomcom.data[0] = TransmitBuffer[0] & ~NCMD_COMPRESSED;
 		if (TransmitBuffer[0] & NCMD_COMPRESSED)
@@ -316,6 +316,12 @@ void PacketGet (void)
 			memcpy(doomcom.data + 1, TransmitBuffer + 1, c - 1);
 		}
 	}
+	else if (c > 0)
+	{	//The packet is not from any in-game node, so we might as well discard it.
+		Printf("Dropped packet: Unknown host (%s:%d)\n", inet_ntoa(fromaddress.sin_addr), fromaddress.sin_port);
+		doomcom.remotenode = -1;
+		return;
+	}
 
 	doomcom.remotenode = node;
 	doomcom.datalength = (short)c;