diff --git a/fs/ksmbd/connection.c b/fs/ksmbd/connection.c
index 8e15ec9e8f43e55401dbde2c7f603f38f03c0d30..4e9ce05374a35990a28a1ad939d0ad32bef1ae76 100644
--- a/fs/ksmbd/connection.c
+++ b/fs/ksmbd/connection.c
@@ -315,8 +315,6 @@ int ksmbd_conn_handler_loop(void *p)
 			continue;
 
 		memcpy(conn->request_buf, hdr_buf, sizeof(hdr_buf));
-		if (!ksmbd_smb_request(conn))
-			break;
 
 		/*
 		 * We already read 4 bytes to find out PDU size, now
@@ -334,6 +332,9 @@ int ksmbd_conn_handler_loop(void *p)
 			continue;
 		}
 
+		if (!ksmbd_smb_request(conn))
+			break;
+
 		if (!default_conn_ops.process_fn) {
 			pr_err("No connection request callback\n");
 			break;
diff --git a/fs/ksmbd/smb2pdu.h b/fs/ksmbd/smb2pdu.h
index 9018d919cdd8a080c1beeaf381af37ec7249d4a8..3fb617c4b60973a91ecc550253a68e04abc74e6e 100644
--- a/fs/ksmbd/smb2pdu.h
+++ b/fs/ksmbd/smb2pdu.h
@@ -109,6 +109,7 @@
 
 #define SMB2_PROTO_NUMBER cpu_to_le32(0x424d53fe) /* 'B''M''S' */
 #define SMB2_TRANSFORM_PROTO_NUM cpu_to_le32(0x424d53fd)
+#define SMB2_COMPRESSION_TRANSFORM_ID cpu_to_le32(0x424d53fc)
 
 #define SMB21_DEFAULT_IOSIZE	(1024 * 1024)
 #define SMB3_DEFAULT_IOSIZE	(4 * 1024 * 1024)
diff --git a/fs/ksmbd/smb_common.c b/fs/ksmbd/smb_common.c
index 8ea2cdda0984d8d6e665c8756efc5871b8a109a4..ff2e738ae7ac0f02eddfb1d69c1658658287b3e4 100644
--- a/fs/ksmbd/smb_common.c
+++ b/fs/ksmbd/smb_common.c
@@ -156,7 +156,19 @@ int ksmbd_verify_smb_message(struct ksmbd_work *work)
  */
 bool ksmbd_smb_request(struct ksmbd_conn *conn)
 {
-	return conn->request_buf[0] == 0;
+	__le32 *proto = (__le32 *)smb2_get_msg(conn->request_buf);
+
+	if (*proto == SMB2_COMPRESSION_TRANSFORM_ID) {
+		pr_err_ratelimited("smb2 compression not support yet");
+		return false;
+	}
+
+	if (*proto != SMB1_PROTO_NUMBER &&
+	    *proto != SMB2_PROTO_NUMBER &&
+	    *proto != SMB2_TRANSFORM_PROTO_NUM)
+		return false;
+
+	return true;
 }
 
 static bool supported_protocol(int idx)