Update ipmentor/tools.py

ipmentor/tools.py

@@ -300,7 +300,13 @@ def subnet_calculator(network: str, number: str = "0", division_type: str = "max
         str: Calculated subnet information in JSON format
     """
     try:
-        number_int = int(number.strip())
+        # Handle empty number parameter (especially for VLSM)
+        number_str = number.strip()
+        if number_str == "":
+            number_int = 0  # Use 0 as default when number is not provided
+        else:
+            number_int = int(number_str)
+            
         result = calculate_subnets(
             network.strip(), 
             number_int,