--- description: Create an origin rule to change the HTTP `Host` header and the resolved DNS record. title: Change the HTTP Host header and DNS record image: https://developers.cloudflare.com/og-docs.png --- [Skip to content](#main-content) > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/rules/llms.txt > Use this file to discover all available pages before exploring further. # Change the HTTP Host header and DNS record Create an origin rule to change the HTTP `Host` header and DNS record. Last updated Aug 24, 2026|Copy as Markdown|[View as Markdown](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/rules/origin-rules/examples/change-http-host-header/index.md)|[Agent setup](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/agent-setup/) The following origin rule overrides the HTTP `Host` header to `hr-server.example.com` for all requests with a URI path starting with `/hr-app/`. It also overrides the DNS record to the same hostname. The `Host` header override only updates the header value; the DNS record override will handle the rerouting of incoming requests. For more information on these overrides, refer to [Origin Rules settings](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/rules/origin-rules/features/). Expression when using the Expression Builder: | Field | Operator | Value | | -------- | ----------- | -------- | | URI Path | starts with | /hr-app/ | Expression when using the Expression Editor: ```txt (starts_with(http.request.uri.path, "/hr-app/")) ``` Value after **Host Header** \> **Rewrite to**: ```txt hr-server.example.com ``` Value after **DNS Record** \> **Override to**: ```txt hr-server.example.com ``` The following example sets the rules of an existing phase ruleset (`$RULESET_ID`) to a single origin rule — overriding the `Host` header of incoming requests and the resolved DNS record — using the [Update a zone ruleset](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/api/resources/rulesets/methods/update/) operation. The response will contain the complete definition of the ruleset you updated. Required API token permissions At least one of the following [token permissions](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/fundamentals/api/reference/permissions/) is required: * `Response Compression Write` * `Config Settings Write` * `Dynamic URL Redirects Write` * `Cache Settings Write` * `Custom Errors Write` * `Origin Write` * `Managed headers Write` * `Zone Transform Rules Write` * `Mass URL Redirects Write` * `Magic Firewall Write` * `L4 DDoS Managed Ruleset Write` * `HTTP DDoS Managed Ruleset Write` * `Sanitize Write` * `Transform Rules Write` * `Select Configuration Write` * `Bot Management Write` * `Zone WAF Write` * `Account WAF Write` * `Account Rulesets Write` * `Logs Write` * `Logs Write` ```bash curl "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/rulesets/$RULESET_ID" \ --request PUT \ --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \ --json '{ "rules": [ { "ref": "hr_app_overrides", "expression": "starts_with(http.request.uri.path, \"/hr-app/\")", "description": "Origin rule for the company HR application", "action": "route", "action_parameters": { "host_header": "hr-server.example.com", "origin": { "host": "hr-server.example.com" } } } ] }' ``` ```json { "result": { "id": "", "name": "Origin Rules ruleset", "description": "Zone-level ruleset that will execute origin rules.", "kind": "zone", "version": "2", "rules": [ { "ref": "hr_app_overrides", "id": "", "version": "1", "action": "route", "action_parameters": { "host_header": "hr-server.example.com", "origin": { "host": "hr-server.example.com" } }, "expression": "starts_with(http.request.uri.path, \"/hr-app/\")", "description": "Origin rule for the company HR application", "last_updated": "2022-06-03T14:42:04.219025Z", "ref": "" } ], "last_updated": "2022-06-03T14:42:04.219025Z", "phase": "http_request_origin" }, "success": true, "errors": [], "messages": [] } ``` Use the `ref` field to get stable rule IDs across updates when using Terraform. Adding this field prevents Terraform from recreating the rule on changes. For more information, refer to [Troubleshooting](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/terraform/troubleshooting/rule-id-changes/#how-to-keep-the-same-rule-id-between-modifications) in the Terraform documentation. Was this helpful? YesNo ## On this page [![](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/_astro/logo.te5VL_aD.svg)Docs](https://docs-durable-objects-instance-replaced-errors.previews.developers.cloudflare.com/) ```json {"@context":"https://schema.org","@type":"TechArticle","@id":"https://developers.cloudflare.com/rules/origin-rules/examples/change-http-host-header/#page","headline":"Change the HTTP Host header and DNS record · Cloudflare Rules docs","description":"Create an origin rule to change the HTTP Host header and the resolved DNS record.","url":"https://developers.cloudflare.com/rules/origin-rules/examples/change-http-host-header/","inLanguage":"en","image":"https://developers.cloudflare.com/og-docs.png","dateModified":"2026-08-24","publisher":{"@type":"Organization","name":"Cloudflare","description":"One platform for your apps, agents, and workforce. Build, secure, and scale without managing infrastructure","url":"https://www.cloudflare.com/","sameAs":["https://github.com/cloudflare","https://www.linkedin.com/company/cloudflare","https://x.com/cloudflare"],"logo":{"@type":"ImageObject","url":"https://developers.cloudflare.com/logo.svg"},"address":{"@type":"PostalAddress","streetAddress":"101 Townsend St","addressLocality":"San Francisco","addressRegion":"CA","postalCode":"94107","addressCountry":"US"},"contactPoint":[{"@type":"ContactPoint","contactType":"Customer Support","url":"https://support.cloudflare.com/","availableLanguage":["English"]},{"@type":"ContactPoint","contactType":"Sales","url":"https://www.cloudflare.com/contact/","availableLanguage":["English"]}]},"isPartOf":{"@type":"WebSite","@id":"https://developers.cloudflare.com/#website","name":"Cloudflare Docs","url":"https://developers.cloudflare.com/"},"keywords":["Headers"]} ```