Release Notes Firmware Update Version 1.04.25_17 for Router NB5580. 24/09/2004 - Enhanced SPI function (Will detect and appear as Stealth to Port Scans even if you have port forwards enabled) - Fixed URL Filter order problem. - Improved VPN functions. Note: You must have 'Block WAN ping response' enabled to use the new 'Port Scan and DoS Protection' mode.