SMTP settings, explained

There are two different SMTP settings involved in sending mail through the gateway, and they're easy to mix up because they're both "SMTP settings" — but they point at different servers and get configured in different places.

1. The gateway's inbound server — what your mail client connects to

This is the server address you put into your email program (Outlook, Thunderbird, your phone's mail app, or a script) when you set it up to send through the gateway:

• Server — the gateway's own address (shown on your account's Configuration page).
• Port — 465 or 587, depending on whether your client expects implicit or STARTTLS encryption.
• Username — your account's own email address.

Every outgoing message your mail client sends goes to this server first. That's the whole point: it's where attachments get stripped out and stored securely before anything continues on to its recipient.

2. Your own relay — where the gateway forwards mail onward

This is the other SMTP server — your real mailbox provider's own outbound server (for example, your Google Workspace or Microsoft 365 SMTP relay, or your ISP's) — that the gateway itself uses to actually deliver the attachment-stripped message once it's done processing it.

You (or, if you were invited to join an existing organization, your admin) configure this once, during onboarding:

• Host — your provider's SMTP hostname, e.g. smtp.gmail.com.
• Port — usually 587.

If your email address is from a recognized provider, the setup form usually fills this in for you automatically. See the guides section for the specific program you're sending from.