Although it was advertised on the product's website, there does not seem to be any support for UPnP within the administrative interface. Nor did the tell-tale UPnP notification appear in the System Notification area of the Win XP SP2 system that we attached to each router's LAN port for testing. (And yes, the WinXP SSDP Discovery Service was enabled on the test computer.)
Port forwarding is available in both static and triggered flavors, however, with 20 and 8 port ranges in both TCP and UDP being specifiable, respectively. Each static port-forwarding rule can be set up to use one of 10 day/time schedules. Ports may also be filtered using eight inbound and eight outbound rule sets to allow or deny access for up to one IP address and range of ports. Four MAC addresses may be allowed or denied LAN and Internet access as well.
Content filtering is another area in which the AR504 offers a variety of options, with domain-based filtering options for up to 9 domains (with selective logging options available). IP address range whitelists can also be established that may bypass the domain filters, though the domain-based filtering is only set up to block DNS queries so entering the IP address of a filtered domain into a web browser is an easy way to bypass that filter. In addition to domain-based filtering, up to 10 keywords within Internet content may be filtered with the AR504.
For the telecommuting crowd, the AR504 supports a wide variety of VPN settings, with eight sessions allowed for PPTP, 16 sessions allowed for IPSec, and support for as many L2TP connections as the router has NAT connections enabled (up to five may be enabled at any given time).
Finally, the AR504 rounds out its feature set with dynamic DNS support (for Dyndns, DHS, and TZO), time setting via NTP server (though it lacks the ability to auto-set the time), the ability to send WakeUp commands to specified LAN hosts, and support for up to eight static routes.