diff --git a/src/cryptonote_config.h b/src/cryptonote_config.h
index 13f0c471b..21f2bf81e 100644
--- a/src/cryptonote_config.h
+++ b/src/cryptonote_config.h
@@ -93,6 +93,7 @@
 
 
 #define BLOCKS_IDS_SYNCHRONIZING_DEFAULT_COUNT          10000  //by default, blocks ids count in synchronizing
+#define BLOCKS_IDS_SYNCHRONIZING_MAX_COUNT              25000  //max blocks ids count in synchronizing
 #define BLOCKS_SYNCHRONIZING_DEFAULT_COUNT_PRE_V4       100    //by default, blocks count in blocks downloading
 #define BLOCKS_SYNCHRONIZING_DEFAULT_COUNT              20     //by default, blocks count in blocks downloading
 #define BLOCKS_SYNCHRONIZING_MAX_COUNT                  2048   //must be a power of 2, greater than 128, equal to SEEDHASH_EPOCH_BLOCKS
diff --git a/src/cryptonote_protocol/cryptonote_protocol_handler.inl b/src/cryptonote_protocol/cryptonote_protocol_handler.inl
index 37157e637..4e3470068 100644
--- a/src/cryptonote_protocol/cryptonote_protocol_handler.inl
+++ b/src/cryptonote_protocol/cryptonote_protocol_handler.inl
@@ -2505,7 +2505,7 @@ skip:
     }
     MDEBUG(context << "first block hash " << arg.m_block_ids.front() << ", last " << arg.m_block_ids.back());
 
-    if (arg.total_height >= CRYPTONOTE_MAX_BLOCK_NUMBER || arg.m_block_ids.size() >= CRYPTONOTE_MAX_BLOCK_NUMBER)
+    if (arg.total_height >= CRYPTONOTE_MAX_BLOCK_NUMBER || arg.m_block_ids.size() > BLOCKS_IDS_SYNCHRONIZING_MAX_COUNT)
     {
       LOG_ERROR_CCONTEXT("sent wrong NOTIFY_RESPONSE_CHAIN_ENTRY, with total_height=" << arg.total_height << " and block_ids=" << arg.m_block_ids.size());
       drop_connection(context, false, false);