Firewall Regel ausgegraut

Hello Christian, 

Thanks for reaching out to Sophos Community. 

It is an explicit deny rule/catch all at the bottom of the Firewall rules which you cannot edit. If a traffic does not match any Firewall rule from the top to bottom, it will hit the explicit deny at the bottom and thus blocking the traffic.

Hope this information helps. Have a nice day and thank you for choosing Sophos.

Regards,

Does this mean that everything I do not explicitly allow from the WAN is blocked or dropped?

Hello,

If there’s a Firewall Rule above that allows the traffic before it hits this explicit deny at the bottom, the traffic will be allowed, but if there’s none that matches until it hits the deny at the bottom, yes, the traffic will be blocked. 

Regards,

... and not only traffic from WAN, but LAN to WAN or internal-to-Internal too.