A new website can load correctly while staff stop receiving mail. Make the web cutover and the mail routing two explicit work packages. The acceptance question is whether the agreed mail records and mail-server targets survive the website change, not whether a browser can open the new home page.
Who should use this acceptance brief
Businesses changing website hosts while retaining email. Use this as a scoped website handover task. Where real system evidence is required, teaching examples are not a substitute.
Source-bound platform fact
Cloudflare explains that standard HTTP proxying does not carry SMTP, IMAP or POP3; MX targets must resolve appropriately, and the MX record itself is DNS-only. Cloudflare: email troubleshooting · Checked 16 October 2026.
Filled teaching example
Synthetic example, not a client case. Finite inputs, expected decisions and counterexamples follow; no live integration is claimed.
On narrow screens, scroll to read the complete table.
| Input / case | Check basis | Expected decision |
|---|---|---|
| web A changes; MX unchanged | approved mail target | preserve |
| MX now points to new web host | unapproved route | stop cutover |
| mail host proxied | standard proxy | technical review |
Run the acceptance exercise
- Export a redacted before-record list with the mail provider’s approved target and priority.
- Compare the proposed zone with that list; treat any changed MX target or mail-host proxy status as a separate decision.
- After authorised cutover, verify DNS and a permitted send/receive test without publishing message contents.
Interpret the result and retain evidence
The fixture compares one MX route and one host-proxy flag; a matching result is only a configuration check. It does not query DNS or send email. Retain the source/provider record, before/after target and observed test time so a supplier cannot substitute an unrelated website uptime screenshot for mail evidence.
Limits before implementation
Not an email-authentication audit, SPF/DMARC guide or permission to change this site’s DNS. Multiple providers, routing products and propagation need a separately approved plan.
Replay the finite example
Save both files in one folder and run with Node22.13 or newer. The example sends no network requests and changes no account or site. Filled inputs and expected outputs · Inspectable functions
node decision-check.mjs website-cutover-mail-record-check.json