# Prepare the App Service custom-domain binding before regional cutover

> Separate target-app preparation from the later DNS change that directs users to it.

- Canonical URL: https://update.dsesecurity.com/updates/dse-20260909-247-prepare-the-app-service-custom-domain-binding-before-regional-cutover/
- Publisher: Detection Systems & Engineering (DSE Security)
- Author: DSE Security Editorial Team
- Published: 2026-09-10T00:27:49+00:00
- Modified: 2026-09-10T01:20:46+00:00
- Last reviewed by DSE: 2026-09-09
- Resource type: Guide
- DSE priority: Information
- Topics: Cybersecurity, Networks & Infrastructure
- Reading time: 2 minutes

## What you need to know

Separate target-app preparation from the later DNS change that directs users to it.

## Potentially affected

Azure App Service regional relocation using a custom domain and a new target app.

## DSE recommendation

Prepare and verify the target binding and application before authorizing the public name's cutover.

## Article

## Source facts

App Service resources are regional and cannot be moved directly across regions; Microsoft describes creating a copy in the destination. Its portal procedure prepares the custom-domain binding on the target with asuid. before remapping the domain name.

For the public multitenant service, domain ownership must be verified for the binding. Once the binding exists, the source says public DNS does not have to point at that App Service endpoint merely to keep the binding in place. [Microsoft Learn](https://learn.microsoft.com/en-us/azure/azure-resource-manager/management/relocation/relocation-app-service).

## Applicability

Identify the source app, destination app and plan, custom name, certificate arrangement and cutover owner. Use this as a sequencing check within a complete regional relocation plan, not as the entire migration procedure.

## DSE recommendation

DSE recommends treating binding preparation and traffic redirection as separately approved milestones. Verify the destination’s application settings and dependencies before asking the DNS owner to remap the name. Preserve the existing name-to-service mapping and an agreed reversal decision. Avoid using public traffic as the first test of whether the destination was configured correctly.

## Verification

Before cutover, inspect the target’s custom-domain binding and complete the approved target application tests. After the authorized name change, check resolution and the intended application transaction from representative client paths. Record which app actually served the request, along with certificate and dependency results. Investigate discrepancies before declaring regional relocation complete.

## Official references

[Microsoft Learn: Relocate Azure App Services to another region](https://learn.microsoft.com/en-us/azure/azure-resource-manager/management/relocation/relocation-app-service). Source retrieved September 9, 2026.

## Primary reference

- Name: Relocate Azure App Services to another region - Azure Resource Manager | Microsoft Learn
- Authority: Microsoft Learn
- URL: https://learn.microsoft.com/en-us/azure/azure-resource-manager/management/relocation/relocation-app-service
- Source publication date: Not stated by the source

## Citation and use

Preferred citation: “Prepare the App Service custom-domain binding before regional cutover,” DSE Security, https://update.dsesecurity.com/updates/dse-20260909-247-prepare-the-app-service-custom-domain-binding-before-regional-cutover/
Publishing principles: https://update.dsesecurity.com/updates/dse-updates-editorial-methodology/
Usage and citation policy: https://update.dsesecurity.com/usage/
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