dstiles - 7:17 pm on Jan 20, 2013 (gmt 0)
The best method I have found for dynamic IPs, including static, broadband and mobile, is to define the full IP range as "dynamic" and then ban offenders for a given period of time, removing the ban at the end of that time. If the IP offends several times within the ban timeout, increase the timeout. Servers and known bad ranges are permanently banned, with holes for good bots.
I run half a dozen computers here off a single static broadband IP. The router connects to the phone line and an 8-way Netgear switch-box fans out the single router output to the local computers, one switched line per computer. Switching is high-speed and automatic. It's worked well for over a decade now. I see no reason why this technique should not work for any router or modem, with the proviso that the modem does not rely on a computer for any reason.