diff --git a/server.py b/server.py
old mode 100644
new mode 100755
--- a/server.py
+++ b/server.py
@@ -36,7 +36,11 @@ outcoming=networkWriter.input
 while True:
   jsonData,binData=incoming.get(timeout=2)
   
-  if jsonData["command"]=="req": # !! index out of range
+  if jsonData["command"]=="init":
+    assert jsonData["blockSize"]==localTree.BLOCK_SIZE
+    assert jsonData["blockCount"]==localTree.leafCount
+    
+  elif jsonData["command"]=="req": # !! index out of range
     print("received request for node #{0}".format(jsonData["index"]))
     nodeHash=localTree.store[jsonData["index"]]