@David-TP I think the Raspbery Pi solution you're talking about is probably Pi-hole - which acts as a DNS proxy but would not do what I want to do in terms of logging (or blocking) outgoing requests...

@David-TP Surely you mean that incoming ports are closed by default? That's not what I'm trying to do here. My IP has been blacklisted by Spamhaus, they have provided examples of SMTP connections...

I'm trying to identify a device gone rogue - I suspect that something is being used as a proxy to fire out spam, possibly a cheap smart plug. But... I can't find any way to block port 25 via the Deco...