The SPI firewall can't be switched off but you can customize it with your own filters. This is made all the more complex as the router supports IPv6 as well as IPv4 and separate filters are created for each type of source and destination address. Intrusion detection can also be activated and alerts send via email or as a pop-up to systems running the Client Manager utility. Basic QoS (quality of service) is provided where you can specify eight applications and choose from three priorities for each one.
Along with the full gamut of wireless security measures the router also supports the fledgling WPS (Wi-Fi Protected Setup) which is designed to make secure connections even easier. However, the main user guide doesn't even acknowledge WPS and Buffalo advised us this feature is currently only supported by Vista's built-in Wireless Manager tool and is provided to allow clients using PC Cards other than Buffalo's to enjoy a one-touch configuration. The Client Manager utility supplied with the PC Card only supports AOSS which is the preferred method when using an all Buffalo setup.
Wireless performance was good as with an 802.11a connection we saw the open source Iometer utility report an average raw read rate of 84Mbps over a one metre link to a Supermicro 3.2GHz Pentium D PC on the LAN. Moving the laptop to the floor below the router with three brick walls in the way saw this fall to 33Mbps. Speeds over 802.11g were in the same ball park with Iometer reporting 80Mbps over a close range link and 36Mbps over the longer range. Alas, real world performance dropped significantly as copying a 690MB file to the PC over close range 802.11a and 802.11g links returned respective averages of 40Mbps and 36Mbps. We also tested with both access points active by simultaneously streaming music to an iTunes client over 802.11g and running Iometer with the laptop linked over 802.11a and saw no drop in performance for the latter.
There has been a mass of controversy surrounding the draft 802.11n standard but the fact that the mighty Cisco has recently announced support will give it a huge boost in acceptance for business use. Note that the WZR-AG300NH is only draft 1.0 compliant but it is offering a veritable feast of wireless features. However, this router is comparatively expensive so unless you really feel the 802.11a support is of benefit then consider D-Link's DIR-655 as this offers a lot more features and equally good performance for a lot less hard cash.