The Miscellaneous page contains parameters that don’t fit into the other subgroups like everything related to time, the option to permit/prohibit the UPnP protocol, and settings to access the router’s local DNS server from the Internet.
The NAT Setting group contains NAT-related settings, as you may guess. On the Port Trigger page you can specify a port visible from the internal network that packets from certain applications in the external network (specified by the numbers of the incoming ports) will be redirected to.
The Virtual Server subgroup is for setting up virtual servers on the internal network which will be accessible from the external network.
The Virtual DMZ page is where you can specify the address of a machine on the intranet that all the packets from the external network will be directed to.
Like a majority of modern routers, the ASUS WL500g Premium has an integrated firewall. It can be set up in the Internet Firewall group. The Basic Config subgroup contains parameters that concern the firewall in general.
Then, you can set up the parameters of filtering of packets from different applications in both directions on the WAN&LAN Filter page.