GoAdmio
GoAdmio Documentation

Resolver Configuration

From the GoAdmio knowledge base.

Resolver Configuration

This page explains the Resolver Configuration screen in the GoAdmio Admin Panel. It controls which DNS resolvers the server uses to look up domain names — affecting everything from website loading to email delivery and SSL validation.

Location: Admin Panel → Networking Setup → Resolver Configuration


Overview

A resolver (also called a recursive DNS server) translates domain names into IP addresses. Every time the server needs to reach a hostname — loading a WordPress update, sending email, validating an SSL certificate, fetching a package — it asks its configured resolver.

If the resolver is slow, rate-limited, or unreachable, everything that depends on DNS slows down or fails. This page lets you choose a resolver preset or enter custom resolver IPs.

> Note: Changing the resolver does not change your server's authoritative DNS zones. It only changes the upstream DNS service the server itself uses for lookups. For authoritative DNS, see DNS Manager and Nameservers.


Presets

The page offers a set of one-click presets that fill in the resolver fields with well-known public DNS services.

| Preset | Resolver IPs | Provider |
|---|---|---|
| Google Public DNS | 8.8.8.8, 8.8.4.4, 2001:4860:4860::8888 | Google LLC |
| OpenDNS Public DNS | 208.67.222.222, 208.67.220.220 | Cisco OpenDNS |
| Quad9 Public DNS | 9.9.9.9, 149.112.112.112 | Quad9 Foundation |
| Cloudflare Public DNS | 1.1.1.1, 1.0.0.1 | Cloudflare |
| Data Center DNS | Resolvers hosted in the same data center as the server | Hosting provider |

Selecting a preset populates the fields below. You can then adjust individual entries.

> Tip: Cloudflare Public DNS (1.1.1.1) is often the fastest option for general-purpose servers. Quad9 (9.9.9.9) filters known-malicious domains by default — useful for shared hosting. Data Center DNS is usually the lowest-latency option because it is on the same network as the server, but may not filter threats and may have stricter rate limits.


Fields

Primary Resolver

The first resolver the server queries.

| Field | Description | Example |
|---|---|---|
| Primary Resolver | IPv4 or IPv6 address of the primary DNS resolver. | 8.8.8.8 |

The panel shows the IP, the country flag, the provider organization, and the provider's ticker (e.g., US Google LLC (GOGL)).

> Note: Always set a Primary Resolver. Without one, the server cannot resolve any hostname and nearly everything breaks.


Secondary Resolver

The resolver the server queries if the primary does not respond.

| Field | Description | Example |
|---|---|---|
| Secondary Resolver | IPv4 or IPv6 address of a second DNS resolver. | 8.8.4.4 |

> Tip: Use a second resolver from the same provider as the primary (e.g., 8.8.8.8 + 8.8.4.4). Mixing providers can cause inconsistent answers and slower failover. If you need redundancy across providers, put the second provider in the Tertiary slot.


Tertiary Resolver (optional)

An optional third resolver.

| Field | Description | Example |
|---|---|---|
| Tertiary Resolver (optional) | IPv4 or IPv6 address of a third DNS resolver. | 2001:4860:4860::8888 |

> Note: A third resolver adds redundancy. Leaving it empty is fine for most servers. If you fill it, prefer an IPv6 or a resolver from a different provider than the primary/secondary.


How to Configure

  1. Log in to the GoAdmio Admin Panel.
  2. Navigate to Networking Setup → Resolver Configuration.
  3. Choose a preset, or enter the IPs manually.
  4. Click Save.
  5. GoAdmio writes the resolver configuration to the system and updates /etc/resolv.conf.
Changes take effect immediately for new lookups. Cached answers may persist briefly (seconds to minutes, depending on TTL).

Verify the Configuration

From a root shell, confirm the active resolvers:

```bash
cat /etc/resolv.conf

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