Uncapping
Uncapping, when talking about cable modems, is refusal to follow one's proper ISP modem settings. It is sometimes done for the sake of bandwidth (i.e. if one buys a 512kbit/s access and then alters it to 10Mbit/s), pluggable interfaces (as by using more than one public ID), or any configurable options a DOCSIS modem can offer.
Uncapping is obviously an undesirable practice, and notoriously difficult to prevent. There has been some controversy surrounding certain ISPs who have begun involving the law in uncapping cases, rather than simply terminating the accounts or wiping the settings, as per tradition.
Uncappers are almost always caught because cable internet providers generally check the configuration files from the head-end nightly.
Methods :
There are several methods used to uncap a cable modem, by hardware or software tricks.
The first technique to enjoy any success employed Motorola modems (such as SB3100, SB4100 and some of the SB4200 models). By spoofing the TFTP server, one could force the modem to accept a different config file than would be expected.
An alternate method employs dhcpforce. By flooding a modem with faked DHCP packets (which contain configuration filename, TFTP IP, etc), one can convince the modem to accept any desired config file, even on one's own server (provided the server is routed, of course).
