I'm not sure if it is the router, or the DD-WRT firmware, or if it happens as well with the regular linksys firmware, but what I do know is that it's plain stupid . My WRT54GS is connected to a switch using Ethernet and the switch connects with my Cable modem which is bridged (no NAT operations). My WRT54GS uses automatic-DHCP configuration and of course I added the gateway ip address to which it is supposed to connect to, which is the bridged cable modem. Unfortunately I also have a DSL Modem which is not bridged and is connected to the switch through Ethernet as well. Everytime the WRT54GS reboots it automatically connects to the DSL modem. How is this possible if STP is disabled for comcast, the gateway address isn't related with DSL router and neither are the DNS addresses? The only way for my WRT54GS to connect to the Cable modem is to select from the list of static or public IP addresses my ISP offers and choose one as a static connection for the WRT54GS (using the Static IP option on the setup tab).