Batch Convert ISP IP Ranges to CIDR

Batch Converting ISP IP Ranges

Internet Service Providers are assigned large blocks of IP addresses from Regional Internet Registries. When analyzing network traffic, configuring abuse filters, or building allowlists, you often need to convert multiple ISP ranges to CIDR notation at once.

Batch Mode Example

Input (one range per line):

24.0.0.0 - 24.15.255.255
24.16.0.0 - 24.23.255.255
24.24.0.0 - 24.27.255.255
24.28.0.0 - 24.29.255.255

Output:

24.0.0.0/12      (1,048,576 IPs)
24.16.0.0/13     (524,288 IPs)
24.24.0.0/14     (262,144 IPs)
24.28.0.0/15     (131,072 IPs)

Why Batch Processing?

Large ISPs may have dozens or hundreds of non-contiguous IP ranges. Processing them one by one is impractical. Batch mode handles all conversions simultaneously.

Use Cases for Batch Conversion

1. Network abuse reporting: Convert an ISP's ranges to CIDR for abuse complaint routing
2. Traffic analysis: Identify which ISP CIDR blocks generate the most traffic
3. Allowlisting: Add all ranges for a trusted ISP to a firewall allowlist
4. Peering decisions: Analyze IP space overlap for BGP peering arrangements
5. Compliance audits: Verify that IP ranges in firewall rules match documentation

Formatting Tips for Batch Input

The batch parser accepts:

• 10.0.0.0 - 10.0.0.255 (spaces around dash)
• 10.0.0.0-10.0.0.255 (no spaces)
• 10.0.0.0 – 10.0.0.255 (en-dash)

Each line is processed independently, so errors in one line don't affect others.

Processing Large Lists

For lists with hundreds of ranges, you can:

1. Export from a spreadsheet to a text file (one range per line)
2. Paste directly into batch mode
3. Copy all results at once with the Copy button
4. Use the results in your firewall rule import tool