Spam & security

Every incoming message is checked before it reaches your inbox — sender authentication, spam scoring, and virus scanning all run automatically. Here’s what those checks mean for you.

Sender authentication

Knobs verifies each message against the standard email authentication checks (SPF, DKIM, and DMARC — the mechanisms that prove a message really came from the domain it claims). When a message fails these checks, you’ll see a warning banner above the message body so you can treat it with appropriate suspicion.

Caution

Be careful with messages carrying an authentication warning — a failed check is a common sign of a spoofed sender. Don’t click links or open attachments unless you’re confident about the source.

Spam filtering

Messages that score as spam are routed to the Spam folder instead of your inbox. The filter is deterministic — it combines the authentication results above with signals like mailing-list headers, so the same message is always treated the same way.

If something legitimate lands in Spam, open the Spam folder to read it — the warning banner explains why it was flagged.

Virus protection

Attachments are scanned on arrival. Messages that fail the virus scan are quarantined and never reach your inbox.

Mail to addresses that don’t exist

When someone mails an address on your domain that doesn’t exist (a typo, or a person who left), Knobs doesn’t silently eat the message:

• The sender gets a standard bounce (“address not found”) — but only when their mail passed authentication, so forged senders can’t use your domain to spray bounces at victims.
• The message itself is shelved for 30 days and listed in an admin-only Undelivered view under Settings → Domains.

Recover an undelivered message (admins)

1. Open Settings → Domains and find the Undelivered section.
2. Review the shelved message — sender, intended recipient, and why it wasn’t delivered.
3. Either create the address (as a mailbox or alias) and re-deliver, or deliver it anyway to an existing mailbox.

This is how you rescue mail sent to jhon@ instead of john@ without asking the sender to resend.

Who can read your mail

Your mailbox is yours. Mail is scoped to you within your workspace — other members, including admins, don’t see your inbox. Messages you send to other members of your workspace are delivered internally to their mailboxes.