diff --git a/SMBLibrary/SMB1/SMB1Header.cs b/SMBLibrary/SMB1/SMB1Header.cs
index beec558..c1148c4 100644
--- a/SMBLibrary/SMB1/SMB1Header.cs
+++ b/SMBLibrary/SMB1/SMB1Header.cs
@@ -16,7 +16,7 @@ namespace SMBLibrary.SMB1
         public const int Length = 32;
         public static readonly byte[] ProtocolSignature = new byte[] { 0xFF, 0x53, 0x4D, 0x42 };
 
-        public byte[] Protocol; // byte[4], 0xFF followed by "SMB"
+        private byte[] Protocol; // byte[4], 0xFF followed by "SMB"
         public CommandName Command;
         public NTStatus Status;
         public HeaderFlags Flags;
diff --git a/SMBLibrary/SMB2/SMB2Header.cs b/SMBLibrary/SMB2/SMB2Header.cs
index 9561348..207d3a6 100644
--- a/SMBLibrary/SMB2/SMB2Header.cs
+++ b/SMBLibrary/SMB2/SMB2Header.cs
@@ -16,7 +16,7 @@ namespace SMBLibrary.SMB2
 
         public static readonly byte[] ProtocolSignature = new byte[] { 0xFE, 0x53, 0x4D, 0x42 };
 
-        public byte[] ProtocolId; // 4 bytes, 0xFE followed by "SMB"
+        private byte[] ProtocolId; // 4 bytes, 0xFE followed by "SMB"
         private ushort StructureSize;
         public ushort CreditCharge;
         public NTStatus Status;