said by toothrot :I can confirm that TWC in NYC pushes down a super wacky config to this device that locks down most of the modem. No way to disable DHCP or do real port forwards. I'll try calling them like the OP did, wish me luck!
The 6141 doesn't do DHCP when online and doesn't do any NAT/PAT so the is no port forwarding to configure. It's a simple bridge not a router.