I know that has to be frustrating!
You will need to have one of your network connections having an ip address of 192.168.1.x where x is some number between 2-254 excluding 99 to connect to the dd-wrt web interface.
I also ran into an issue where my home network had to be something other than starting with 192.168.0.
Seems like it has something to do with the LAN interface on the antminer defaulting to 192.168.0 addresses.
Here are the steps I would suggest:
1) Change your ip on your laptop to 192.168.1.5 (default gateway does not matter and whatever netmask should work here) and then goto http://192.168.1.99 and login with root/root.
2) Click on network then click edit on the WAN entry.
3) Change the WAN interface to
IP: 192.168.8.99
Gateway: of 192.168.8.1
subnet mask: 255.255.255.0
also change dns to 192.168.8.1 and also add 8.8.8.8 for good measure
click save and apply
YOU WILL LOSE CONNECTION AT THIS POINT and Its OK
4) Change your laptop network connection back to normal and connect to your router's web interface
5) On your router you will have to change specifically the DHCP settings to give out addresses in the range 192.168.8.2-192.168.8.75 or something less than 100 AND make the LAN IP of the router to be 192.168.8.1.
6) YOU WILL AGAIN LOSE CONNECTION UNTIL YOUR ROUTER REBOOTS AND YOU GET A new IP adress in the 192.168.8 range and then connect to your antminer on http://192.168.8.99 and configure for your pool.
Be sure and take out all the "default" mining setting or you could still be making money for bitmain
Hope that helps!
will try this now, thanks