Did you put current configuration file when you update ?
If so do a reset and turn your settings by hand.
Do your dir reset every 24h ?
Do your modem have a DHCP server if so either bridging
modem or set your dir to dynamic IP.
What i first did was a factory default reset!
Updated firmware, and made all settings by hand. Just a few ports for c-s server, web-cam, Webcamxp and for a streaming application and ftp.
Then i turned of QoS Engine, disabled WISH, disabled SPI the rest if default.
My modem have a DHCP, and settings are dynamic IP
I cant say it's every 24 h, for example last night around 10 a clock the last comp in teh network got turned off for the night.
This morning at 08:00 no internet, and forgot to mention this earlier, when this happens i can't access the router... Its say it busy! or something like that, I have a password to login and just to be sure i turned the MAC Address Filter on. Thought first that someone was fiddling around with my router.
