Thanks for clarifying, that is what I concluded after having messed about with it a bit, hence the firewall rule mentioned in the previous post. It is far from clear if going by the wording on the setup-page though. "By default deny access to UPnP & NAT-PMP?" surely sounds like it controls which clients should access it, not which clients can be forwarded to.
To Tikomotel: Thanks, the dnsmasq link you gave me had the information I needed, the correct location of dnsmasq.conf, which is: /usr/local/etc/. It also turns out that editing the service.inc file probably works as well, it looked like it didn't work because dnsmasq has a hardcoded limit of 10000 as cache-size.
::Trym