Comcast doesn't advertise these addresses as a product, but they're its residential resolvers: each reverse-resolves to cdns01 or cdns02.comcast.net inside Comcast's own network (AS7922), which we checked on 24 October 2026. Xfinity gateways hand them out automatically. Comcast was one of the first big US ISPs to deploy IPv6 to homes, so most Xfinity customers have native IPv6 alongside a public IPv4 address, without carrier-grade NAT. Xfinity's own gateways often don't let you change the DNS they hand out; set DNS per device or use bridge mode with your own router.
Facts
- Brands
- Comcast, Xfinity
- CGNAT
- No
- IPv6
- Yes
- ASNs
- AS7922
DNS servers
75.75.75.75 75.75.76.76 2001:558:feed::1 2001:558:feed::2
Frequently asked questions
What are Comcast's DNS servers?
75.75.75.75 and 75.75.76.76 for IPv4, and 2001:558:feed::1 and 2001:558:feed::2 for IPv6.
Does Comcast Xfinity use CGNAT?
Not for standard home internet: Xfinity customers get a public IPv4 address, so port forwarding works. They also get native IPv6.
Can I change DNS on an Xfinity gateway?
Xfinity gateways often lock the DNS setting. Change DNS on each device (on a Mac: System Settings › Network › Details › DNS), or put the gateway in bridge mode and use your own router.