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What is 75.75.75.75?

75.75.75.75 is the primary DNS resolver address for Comcast Xfinity DNS, run by Comcast. Here's what it does, whether it's safe, and a way to time it from your own connection.

Updated 4 min read

What is 75.75.75.75?

75.75.75.75 is the primary DNS resolver address for Comcast Xfinity DNS, operated by Comcast. Comcast's default anycast resolvers for Xfinity customers in the United States.

Operator
Comcast
This address
75.75.75.75 (primary)
Paired address
75.75.76.76
  • No-log : no
  • DNSSEC : yes
  • Malware blocking : no
  • Ad blocking : no
  • Family filter : no

Primary and secondary — why there are two

75.75.75.75 is Comcast Xfinity DNS's primary address — the one your device queries first. Comcast Xfinity DNS also publishes a secondary, 75.75.76.76, as an automatic fallback. Configuring both is recommended: DNS is critical infrastructure, and a second address means a momentary problem with one server doesn't take your connection offline. Both resolve the same names with the same features, so there's no downside to listing both.

Can you time 75.75.75.75 from a browser?

Not directly. Comcast Xfinity DNS publishes no browser-reachable encrypted-DNS (DoH) endpoint for 75.75.75.75, and a browser can't send a plain DNS query to a raw IP — so there's no honest way to time this address from a web page. To measure it, set 75.75.75.75 as your DNS and run the full DNS speed test, or use dig @75.75.75.75 example.com from a terminal.

Should you use it?

Comcast's default anycast resolvers for Xfinity customers in the United States.

Best for: Xfinity subscribers.

Like any public resolver, Comcast Xfinity DNS adds a small round trip compared with your ISP's default DNS, and it can't optimize CDN routing as tightly as a resolver peered locally with your network in every case. Use the live timing check above, or the full DNS speed test, to see whether it's actually faster than what you have now.

To use Comcast Xfinity DNS, set 75.75.75.75 as your primary DNS and 75.75.76.76 as the secondary — see the device and router setup guides .

75.75.75.75 — frequently asked questions

Is 75.75.75.75 safe to use?

Yes. 75.75.75.75 is a legitimate public DNS address operated by Comcast (Comcast Xfinity DNS). An ISP resolver subject to Comcast's privacy practices; not a no-logging service. Reachable only from within Comcast's network.

Is 75.75.75.75 free?

Yes — Comcast Xfinity DNS is a free public resolver. Point your device or router's DNS at 75.75.75.75 (primary) and 75.75.76.76 (secondary).

Does 75.75.75.75 log my activity?

An ISP resolver subject to Comcast's privacy practices; not a no-logging service. Reachable only from within Comcast's network.

Is 75.75.75.75 faster than my ISP's DNS?

It can be, but it depends on your location and network — and 75.75.75.75 has no browser-reachable encrypted-DNS (DoH) endpoint, so it can't be timed from this page. Set it as your DNS and run the full DNS speed test, or compare it with dig or nslookup from your device.

Do I also need the secondary 75.75.76.76?

It's recommended. 75.75.75.75 is Comcast Xfinity DNS's primary address and 75.75.76.76 is the secondary. Configuring both means that if the primary is briefly unreachable your device falls back to the secondary automatically instead of losing DNS. They resolve identically — the second address is purely a backup.