I am a real newbie at networking, routers etc. Due to DSS-PSI requirements I have had to upgrade my firewall and the BT Smarthub on ADSL will not cut the mustard. I have bought a DIR-880l and delivery happened some while ago, but I couldn't get time to set it up. I have discovered that I stupidly ordered the wrong item and it needed a dsl modem and it is too late to return it.
I have a BT Smarthub and tried to set it up as a modem only (Wifi off and DCHP off), but although it will connect to BT via PPoE, the D-Link router connects then drops straight out. The only way I can get the two to see each other is to a) leave DCHP on, 2) set the IP range on the Smart Hub to 192.168.1.64 to 192.168.1.65 and I get internet. Trouble is I no longer get IPv6 only IPv4 and I am not sure how secure this is. I am into day 5 of trying different set ups, but must acknowledge I don't know enough to fix this. Can anyone talk me through the settings or make any suggestions?

I am not sure if this forum is just for US D-LInk, but cannot find one for UK!