# backup.example.net

← All inbound domains

## DNS status error

Cached a few minutes — use Re-check after publishing. Unlike outbound, inbound needs an MX pointing at this server.

MX error
Host / name backup.example.net
Type MX
Value 10 mail.primary.example.net.

No MX points at mail.example.org (this server). Publish the record below, or wait for DNS to propagate and Re-check.

## Upstream

Where accepted mail is handed off. Not a mailbox.

Host Port TLS to upstream

## MX record to publish

Add this MX so the internet delivers here. Keep any existing primary MX if this is backup-MX.

Host / name
backup.example.net
Type MX
Value
20 mail.example.org.

## Valid recipients

Who this domain accepts on port 25. Same idea as an application’s address mode: a list, or any address at the domain.

Who to accept
Addresses (one per line or comma-separated) postmaster@backup.example.net abuse@backup.example.net

Unknown recipients are rejected at RCPT so this relay does not generate backscatter.

Every address at this domain is accepted and forwarded. Prefer a list unless the upstream rejects unknowns — otherwise this relay may generate backscatter.

## Danger zone

Stops accepting mail for this domain. Does not touch outbound sending domains.

Delete inbound domain