Do not accept emails from ANY (Avoid open relay) - applicable to MTA mode only
Critical
Explanation
Adding Any will result in an open relay, allowing anyone on the internet to send emails through Sophos Firewall.
Resolution
- Go to PROTECT > Email > General settings.
- Ensure that SMTP deployment mode is set to
Mail Transfer Agent (MTA).
Note
You are at the MTA mode if you are seeing the Switch to legacy mode button. The legacy mode is not compatible with Sandstorm for Email.
- Go to PROTECT > Email > ... > Relay settings.
- Ensure that
Anyis not added under Host based relay > Allow relay from hosts/networks. - Click Apply.