SignalBridge

Domain email setup

Your email provider may change. Your domain must remain yours.

A durable business-email setup separates registrar ownership, DNS control and mailbox hosting. That makes migration possible and reduces the chance that one lost login becomes a company-wide outage.

Layer 1

Domain registrar

Legal and operational control of the domain. Use strong recovery, MFA and named ownership.

Layer 2

Authoritative DNS

Controls mail routing and authentication. Document who can change records and how rollback works.

Layer 3

Email provider

Hosts mailboxes, calendars and related services. It should be replaceable without transferring the domain.

Safe setup order

1

Verify domain ownership

Add the provider's verification record without changing mail flow.

2

Create every receiving address

Users, aliases, shared addresses and catch-all behaviour must exist before MX cutover.

3

Prepare SPF

Authorise legitimate senders and maintain one consolidated SPF record.

4

Enable DKIM

Publish the provider's signing records and confirm messages are signed.

5

Stage DMARC

Begin with visibility, review reports and move enforcement carefully.

6

Change MX

Route inbound mail only after addresses and tests are complete.

7

Test the whole path

External inbound, outbound, replies, aliases, forms, invoices and calendar invitations.

8

Document recovery

Store ownership, provider, records, renewal dates and rollback values outside the mailbox being protected.

Good architecture

Independent and reversible

  • The company controls the registrar account.
  • DNS changes are logged and recoverable.
  • Mailbox addresses are inventoried.
  • SPF, DKIM and DMARC are monitored.
  • Export and migration routes have been tested.

Fragile architecture

Bundled and undocumented

  • A contractor personally owns the domain.
  • The email provider also controls all recovery paths.
  • Multiple unknown SPF records exist.
  • Aliases are undocumented.
  • No one knows the original MX values.

Provider choice

Fastmail

Focused email, domains, aliases, calendars and contacts.

Proton

Privacy-led email and encrypted services.

Microsoft 365

Email within Outlook, Exchange, Office and Teams standardisation.

Final rule

Never solve email convenience by surrendering domain control.

The provider can be bundled with other tools. Ownership, recovery and exit documentation cannot be outsourced.

Primary evidence

Provider documentation checked for this decision.

Evidence reviewed 20 July 2026. Product details and commercial terms can change; verify final configuration with the provider.