SMTP Proxy blocking all other SMTP-Traffic

Hello everybody,

I have an issue with the SMTP-Proxy on our Firewall.

We are running a few applications on our datacenter which come with a simple SMTP-Service that is supposed to send out notification mails and such..

Usually configuring this just takes 5 minutes. However, I am not able to use this service without the SMTP-Proxy on the Sophos Firewall.

I tried to create a firewall-rule for all the typical SMTP-Ports outbound and disabled the Sophos-SMTP-Proxy.

When I tried to connect to the SMTP-Server outside, I get a timeout.

Next steps: Verify credentials > check

Test connection on another network > check

Try Port 25, 587 > still the same, working on other networks

Enable Sophos-SMTP-Proxy and use the Proxy >> SMTP is working.

>> Conclusion:

For me it looks like that even tough I disabled the SMTP-Proxy, the Sophos Firewall does not allow me to use SMTP without the SMTP-Proxy, which makes disabling it kind of pointless. I am able to go around this for now but I would like to know if this is intended or a bug?

Greetings