Public DNS Providers and Their Resolver Addresses
Common public DNS services, their resolver IPs, and operational characteristics.
Public DNS resolvers are operated by different organizations and expose fixed IP addresses that can be configured on devices, routers, or servers. Configuration is simple, but resolver choice affects latency, routing behavior, filtering outcomes, and operational reliability.
For deeper discussion on whether public DNS is worth it, see:
Google Public DNS
Google Public DNS is a globally distributed resolver focused on correctness and availability.
- Primary (IPv4): 8.8.8.8
- Secondary (IPv4): 8.8.4.4
Characteristics:
- No ad or content filtering by default
- Widely reachable from most networks
- Often used as a baseline resolver in diagnostics and tooling
Cloudflare DNS (1.1.1.1)
Cloudflare operates a large anycast DNS network with multiple resolver variants.
Standard Resolver
- Primary (IPv4): 1.1.1.1
- Secondary (IPv4): 1.0.0.1
Malware Blocking
- IPv4: 1.1.1.2 / 1.0.0.2
Malware + Adult Content Blocking
- IPv4: 1.1.1.3 / 1.0.0.3
Characteristics:
- Resolver behavior depends on address selection
- Filtering is implemented at the DNS layer
- Routing and performance can vary by ISP and region
Quad9 (9.9.9.9)
Quad9 is a security-focused public resolver operated by a non-profit foundation.
Default (Threat Blocking)
- Primary (IPv4): 9.9.9.9
- Secondary (IPv4): 149.112.112.112
Unsecured (No Blocking)
- IPv4: 9.9.9.10
Characteristics:
- Default resolver blocks known malicious domains
- Policy-driven blocking can affect application behavior
- Often used in security-conscious environments
AdGuard DNS
AdGuard DNS offers multiple resolver endpoints with different filtering policies.
Default (Ad & Tracker Blocking)
- Primary (IPv4): 94.140.14.14
- Secondary (IPv4): 94.140.15.15
Family Protection
- IPv4: 94.140.14.15 / 94.140.15.16
Non-Filtering
- IPv4: 94.140.14.140 / 94.140.15.140
Characteristics:
- DNS-level ad and tracker blocking
- Filtering can break applications that share domains for core services
- Behavior varies significantly by selected endpoint
OpenDNS (Cisco)
OpenDNS is operated by Cisco and provides both consumer and enterprise-oriented DNS services.
Home Resolver
- Primary (IPv4): 208.67.222.222
- Secondary (IPv4): 208.67.220.220
FamilyShield
- IPv4: 208.67.222.123 / 208.67.220.123
Characteristics:
- Policy-based filtering options
- Often paired with account-based configuration
- Common in managed and enterprise networks
High-Level Comparison
| Provider | Filtering Behavior | Typical Use Case |
|---|---|---|
| Google DNS | None | Baseline resolution, diagnostics |
| Cloudflare | Optional | Performance-focused, optional filtering |
| Quad9 | Default blocking | Security-oriented environments |
| AdGuard | Optional | Ad/tracker blocking via DNS |
| OpenDNS | Optional | Managed filtering and policy control |
Operational Notes
- Resolver choice can influence latency and CDN routing, even when physical distance is small.
- DNS-level filtering applies blunt policy and may cause unexpected failures.
- Resolver behavior can change over time due to routing, policy, or upstream shifts.
- Different ISPs can reach the same resolver IP via very different network paths.
Related reading:
Closing
Public DNS resolvers are easy to configure but hard to evaluate in isolation. The same resolver can behave very differently depending on network topology, peering relationships, and access patterns.
Treat resolver choice as an operational dependency rather than a one-time tweak.
Written by the Infra Atlas author
I work on infrastructure and software systems across layers: writing code, shipping products, and dealing with the practical trade-offs of hosting, memory, and network behavior in production. When this site says it covers “layer 3 to layer 9,” it’s half a joke and half a truth: from routing and packets, up through operating systems, applications, and the human decisions that actually cause outages.
Infra Atlas is a collection of field notes from that work. Some pages may include affiliate or referral links as a low-key way to support the site. Think of it as buying me a coffee while I write about why systems behave the way they do.