I'm having play with a single ethernet port Fonera on which I currently have a recent snapshot of Kamikaze 8.x.
The configuration I require is as follows
ADSL ---> Modem <-----PPTP----> eth0 Fonera
LAN ------------------> eth0:1 Fonera
WLAN -----------------> ath0 Fonera
I need LAN/WLAN bridged and traffic from the Modem to go though a firewall.
Now the dd-wrt forums have a post for a similar request - http://www.dd-wrt.com/phpBB2/viewtopic.php?t=15663
So ideally eth0 will be in the 192.168.1.x zone with a connection to the modem on 192.168.1.138 which then provides the PPTP connection required by my ISP.
LAN/WLAN will be in the same zone 192.168.0.x with the Fonera providing DHCP, DNS and NTP etc.
Yes I know I'd be much better off with a multi port device rather than the single port Fonera, and I have an AR7 based Asus unit that I'm waiting for a newer Kamikaze release to get working.
Steve