cfcname

cfcname is a small Go tool that finds and bulk-rewrites CNAME records across every zone in a Cloudflare account. Point it at a target hostname and it lists every matching record; give it a replacement and it updates them all in place. Useful when a backend, CDN endpoint or load balancer is renamed and dozens of zones still point at the old name.

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Table of Contents

• Table of Contents
• How it works
• Usage
• Building
• License

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How it works

1. Authenticates against the Cloudflare API with the given API token.
2. Lists every zone the token has access to.
3. Fetches the CNAME records of all zones concurrently, one goroutine per zone.
4. Selects the records whose target matches -target-url — either as an exact match (-full-url) or as a suffix of the record's target (the default).
5. Prints the matching records grouped by zone. If no -new-url is given, it stops here, so the tool is a read-only search by default.
6. If -new-url is given, it rewrites each matching record and prints its before/after state. In suffix mode only the matched suffix is replaced, so the record's own prefix is preserved: app.old.example.com becomes app.new.example.com.

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Usage

Build or download the cfcname binary, then run it with the required flags.

List every record across all zones that points at something ending in old.example.com:

./cfcname -token 'CF_API_TOKEN' -target-url old.example.com

Rewrite them to new.example.com, keeping each record's own prefix:

./cfcname -token 'CF_API_TOKEN' -target-url old.example.com -new-url new.example.com

Match and replace one exact target instead of a suffix:

./cfcname -token 'CF_API_TOKEN' -full-url -target-url lb1.old.example.com -new-url lb2.new.example.com

Flags

Flag	Short	Default	Description
-token	-t	(required)	Cloudflare API token
-target-url	-u	(required)	Target hostname to look for in CNAME records
-new-url	-n	(empty)	New target to write. Leave empty to only list the matching records
-full-url	-f	false	Match -target-url as the record's full target instead of a suffix

Note: the API token needs Zone:Read and DNS:Edit permissions on every zone you want it to touch. Run the tool without -new-url first and check the listed records — with -new-url it updates everything it matched, across every zone, with no further confirmation.

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Building

To build the binary:

go build -o bin/cfcname .

The resulting binary will be in the bin folder.

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License

cfcname is licensed under GPL-3.0-only. See LICENSE file for details.