CIDR Match — IP Range Checker

About

CIDR Match shows you, at a glance, whether the IP addresses a web page connects to fall within a CIDR list you define.

Paste your IPv4 CIDR ranges once in the options page. Then, for every page you visit, the popup adds a column marking each connection's IP as a match (✔) or not (✖). The toolbar icon is color-coded green/red based on the main page's IP, so you get instant verification without even opening the popup.

Use it to:
- Verify split-tunnel VPN / policy-based routing is sending a site over the path you expect
- Check a service against a firewall allowlist or blocklist 
- Sanity-check geo/ASN IP allocations 
- Confirm a request is hitting your CDN's edge ranges and not the origin

Privacy first: all matching happens locally in your browser. Nothing is logged, uploaded, or sent anywhere. Your ruleset is stored only on your device.

This extension is a derivative work based on the open-source IPvFoo project (Apache-2.0), with custom CIDR rule matching added. It is not affiliated with or endorsed by the upstream author.