diff --git a/common/xrdp_constants.h b/common/xrdp_constants.h
index 46fffeca..50be8536 100644
--- a/common/xrdp_constants.h
+++ b/common/xrdp_constants.h
@@ -38,6 +38,10 @@
  ******************************************************************************/
 
 #define INFO_CLIENT_NAME_BYTES  32
+/**
+ * Maximum length of a string (two bytes + len), excluding the terminator
+ * [MS-RDPBCGR] TS_INFO_PACKET(2.2.1.11.1.1)
+ */
 #define INFO_CLIENT_MAX_CB_LEN  512
 
 #define XRDP_MAX_BITMAP_CACHE_ID  3