said by Kearnstd:
so a question then. If I went IPV6 I can use a router then? and instead of the router assigning IPs instead Comcast does the DHCP even for LAN clients?
More I am curious how does this effect SAMBA shares and does it still keep the public internet from seeing them.
Maybe I can help clear this up.
Comcast will assign a /128 for their on-link network. Comcast will then assign you a routed block (/64 for now, could be /60 or /56 in the future). The routed block will be routed to your on-link network address.
For your personal network, you could implement the same firewall policy as NAT has (SPI firewall, blocking incoming traffic unless there is an associated state entry). I know D-Link support this a pre-set configuration option. I haven't had experience with other consumer routers as of late.
The different with v4 is you eliminate overloading (the broken part of NAT), as everything is assigned a global unique address.