diff --git a/include/ki/protocol/net/Session.h b/include/ki/protocol/net/Session.h
index f3b7682..e877319 100644
--- a/include/ki/protocol/net/Session.h
+++ b/include/ki/protocol/net/Session.h
@@ -17,6 +17,22 @@ namespace protocol
 {
 namespace net
 {
+	enum class SessionCloseErrorCode
+	{
+		NONE,
+		APPLICATION_ERROR,
+
+		INVALID_FRAMING_START_SIGNAL,
+		INVALID_FRAMING_SIZE_EXCEEDS_MAXIMUM,
+
+		UNHANDLED_CONTROL_MESSAGE,
+		UNHANDLED_APPLICATION_MESSAGE,
+		INVALID_MESSAGE,
+
+		SESSION_OFFER_TIMED_OUT,
+		SESSION_DIED
+	};
+
 	enum class ReceiveState
 	{
 		// Waiting for the 0xF00D start signal.
@@ -106,7 +122,7 @@ namespace net
 
 		/* Low-level socket methods */
 		virtual void send_packet_data(const char *data, const size_t size) = 0;
-		virtual void close() = 0;
+		virtual void close(SessionCloseErrorCode error) = 0;
 	private:
 		/* Low-level networking members */
 		uint16_t m_maximum_packet_size;
diff --git a/src/protocol/net/ClientSession.cpp b/src/protocol/net/ClientSession.cpp
index db70956..9232a5a 100644
--- a/src/protocol/net/ClientSession.cpp
+++ b/src/protocol/net/ClientSession.cpp
@@ -72,7 +72,7 @@ namespace net
 			break;
 
 		default:
-			close();
+			close(SessionCloseErrorCode::UNHANDLED_CONTROL_MESSAGE);
 			break;
 		}
 	}
@@ -87,9 +87,9 @@ namespace net
 		}
 		catch (parse_error &e)
 		{
-			// The SESSION_ACCEPT wasn't valid...
+			// The SESSION_OFFER wasn't valid...
 			// Close the session
-			close();
+			close(SessionCloseErrorCode::INVALID_MESSAGE);
 			return;
 		}
 
@@ -98,7 +98,7 @@ namespace net
 				std::chrono::steady_clock::now() - m_connection_time
 			).count() > KI_CONNECTION_TIMEOUT)
 		{
-			close();
+			close(SessionCloseErrorCode::SESSION_OFFER_TIMED_OUT);
 			return;
 		}
 
@@ -136,7 +136,7 @@ namespace net
 		{
 			// The KEEP_ALIVE wasn't valid...
 			// Close the session
-			close();
+			close(SessionCloseErrorCode::INVALID_MESSAGE);
 			return;
 		}
 
@@ -158,7 +158,7 @@ namespace net
 		{
 			// The KEEP_ALIVE_RSP wasn't valid...
 			// Close the session
-			close();
+			close(SessionCloseErrorCode::INVALID_MESSAGE);
 			return;
 		}
 
diff --git a/src/protocol/net/ServerSession.cpp b/src/protocol/net/ServerSession.cpp
index 5da2d09..72efe98 100644
--- a/src/protocol/net/ServerSession.cpp
+++ b/src/protocol/net/ServerSession.cpp
@@ -78,7 +78,7 @@ namespace net
 			break;
 
 		default:
-			close();
+			close(SessionCloseErrorCode::UNHANDLED_CONTROL_MESSAGE);
 			break;
 		}
 	}
@@ -95,7 +95,7 @@ namespace net
 		{
 			// The SESSION_ACCEPT wasn't valid...
 			// Close the session
-			close();
+			close(SessionCloseErrorCode::INVALID_MESSAGE);
 			return;
 		}
 
@@ -104,14 +104,14 @@ namespace net
 				std::chrono::steady_clock::now() - m_connection_time
 			).count() > KI_CONNECTION_TIMEOUT)
 		{
-			close();
+			close(SessionCloseErrorCode::SESSION_OFFER_TIMED_OUT);
 			return;
 		}
 
 		// Make sure they're accepting this session
 		if (accept.get_session_id() != m_id)
 		{
-			close();
+			close(SessionCloseErrorCode::INVALID_MESSAGE);
 			return;
 		}
 
@@ -134,7 +134,7 @@ namespace net
 		{
 			// The KEEP_ALIVE wasn't valid...
 			// Close the session
-			close();
+			close(SessionCloseErrorCode::INVALID_MESSAGE);
 			return;
 		}
 
@@ -156,7 +156,7 @@ namespace net
 		{
 			// The KEEP_ALIVE_RSP wasn't valid...
 			// Close the session
-			close();
+			close(SessionCloseErrorCode::INVALID_MESSAGE);
 			return;
 		}
 
diff --git a/src/protocol/net/Session.cpp b/src/protocol/net/Session.cpp
index 6a995c8..9807773 100644
--- a/src/protocol/net/Session.cpp
+++ b/src/protocol/net/Session.cpp
@@ -104,7 +104,7 @@ namespace net
 					// correctly.
 					if (m_start_signal != KI_START_SIGNAL)
 					{
-						close();
+						close(SessionCloseErrorCode::INVALID_FRAMING_START_SIGNAL);
 						return;
 					}
 
@@ -126,7 +126,7 @@ namespace net
 					// stop processing data.
 					if (m_incoming_packet_size > m_maximum_packet_size)
 					{
-						close();
+						close(SessionCloseErrorCode::INVALID_FRAMING_SIZE_EXCEEDS_MAXIMUM);
 						return;
 					}