[PLUG] question on how to fix a mysterious DNS address problem

[American Citizen]

Hello all:

I am still puzzled as to where the mysterious 10.0.18.1 address is 
coming from, as looking at my cable modem / router, Netgear Gateway 
C6300v2 router does NOT seem to show any VPN address at all being used.

But I did find out something on this Netgear which needs to be changed.

On the advanced settings page it shows that the IPV6 DNS servers are

2001:0558:feed:0000:0000:0000:0000:0001 (and ::::0002)

both of these are Comcast Cable Communications LLC located in New Jersey.

What IPV6 address can be used to point to a different nameserver? I am 
reluctant to use IPV6 DNS from Comcast. I am also reluctant to use 
Google also, because DNS lookups can be logged.

I did lock the resolv.conf file until I can figure out where the odd 
10.0.[16,17,18,19].1 address are really coming from.

Did Netgear stick in an invisible VPN connection? I don't see anything 
in the Netgear Router admin pages on this VPN operation.

Randall