General Settings: QoS
The QoS subgroup contains one page only – you can specify and view QoS rules here.
General Settings: NAT
The NAT subgroup offers only one page until you enable NAT. This page is nothing else but an editable table of static routes. When NAT is enabled, the subgroup offers five pages among which you can’t find a routing table. We think it is a serious drawback since you often have to write routes in even with enabled NAT. As for the table proper, it contains all the necessary fields including a field that defines the route zone (LAN/WAN). You can use either a full-featured version of NAT or a simplified version called Fast NAT, which leads to interesting consequences (see below) but has limitations concerning certain protocols.
As for the pages that become available on your turning NAT on, the first of them is Port Forwarding where you can specify the appropriate rules.
The Virtual Server page allows to set up virtual servers on the router’s local network.
The Special Applications page is for defining port triggering rules.
The router’s support for the UPnP protocol is enabled or disabled on the UPnP Settings page.
The ALG Settings page contains a long list of specific applications whose rules are enabled by simply checking the corresponding checkbox.