- If you are not using a router, the first hop 10.xx.xx.xx address on a tracert will be your Charter UBR. The 10.xx.xx.xx address is the Charter router's private side address of your Default Gateway.
- If you tracert through the gateway, the Charter UBR private IP address will reply.
- If you tracert to your Charter's Default Gateway the UBR's public gateway IP address will reply.
- If you use a home router, the router's address may or may not show as the first hop depending on the type of router you are using.
The cable modem is just a transparent bridge and will not show on a tracert.
More information here on the tracert first hop address.
»homepage.ntlworld.com/ro ··· ml#ubrip
From Stan Gunn's post here