Mail relay
Infra > Mail relay. The SMTP server that carries confirmations, password resets and administrator notices. It is infra because it is a third-party service reached by host and port, with credentials - the same nature as a route's upstream.
Several features are switches with nothing behind them until this is set: self-registration with a confirmed address, password reset links, the one-time code by e-mail, and the daily digest.
The relay
- Host, Port, Security -
STARTTLS,TLSor none. - Sender address - it lives here because a provider only accepts the account it authenticated. Empty means the account, as long as the account is itself an address. Below the field, the console shows what recipients will actually see, name and address combined.
Then the credentials, as two separate forms rather than one generic set of boxes:
| Mode | When |
|---|---|
| Password | An account and a secret. What every transactional relay uses, and what Gmail accepts with an application password |
| OAuth2 | A token minted by client credentials stands in for the password (XOAUTH2). The only way into Microsoft 365, which no longer accepts a password over SMTP |
OAuth2 asks for the token URL (your tenant's token endpoint), the client ID, the client secret, and a scope - left empty it uses Microsoft's SMTP scope.
Send a test
Pick which message, which language, and the recipient (your own address by default), and a real message goes through the relay with fake values but the real look. This is the fastest way to find out that a port is closed or a sender refused.
Daily digest
Once a day, the administrators who carry an e-mail address are told which accounts are about to lose access, which just did, which vault entries are about to reach their reminder date - and, first, which certificates are about to expire or have expired. A certificate issued automatically (ACME) is renewed weeks before its end, so one that shows up here is one whose renewal has been failing, and the line says so.
- Hour - read in the gateway's own clock, which the field prints under it (time and zone).
- Look ahead - how many days forward to report, one to ninety.
A day with nothing to say sends nothing. With no relay configured the notice stays owed and goes out the morning a relay answers.
Traps
- A typed secret blocks Save. The password and the client secret must be moved into the vault first; that is the only way they get stored. The button stays disabled until they are.
- The sender name is not typed anywhere. The display name in front of the address is the application's name, from Built-in pages, Branding, resolved when the message is sent. Only the address is here.
- Test before you announce. The relay is the judge of an address, not the console.