diff --git a/artiq/protocols/logging.py b/artiq/protocols/logging.py
index 47e646d47..e69f76223 100644
--- a/artiq/protocols/logging.py
+++ b/artiq/protocols/logging.py
@@ -61,7 +61,7 @@ class Server(AsyncioServer):
                     return
                 line = line[:-1]
                 linesplit = line.split(":", 3)
-                if len(linesplit) != 2:
+                if len(linesplit) != 4:
                     logger.warning("received improperly formatted message, "
                                    "dropping connection")
                     return