How to Change DNS on a Mercusys Router

Your Mercusys router shipped from the factory pointed at your ISP's DNS resolvers. Those resolvers are often overloaded, occasionally inject ads into NXDOMAIN responses, and can log every query your household makes. Switching to a faster, more private resolver takes under three minutes at the router level — and when you do it there, every phone, laptop, smart TV, and thermostat on your network benefits immediately, with no per-device changes required.

Why Change DNS at the Router Instead of Per Device

Per-device DNS changes are fragile. DHCP lease renewals overwrite them. VPN profiles override them. OS updates on phones reset them silently. Setting DNS at the Mercusys router level means the change is persistent and network-wide. On Mercusys firmware, DNS is configurable in two distinct places: the WAN settings (what the router uses for upstream resolution) and the DHCP server settings (what addresses the router pushes to client devices). In most setups you need to configure both to fully override your ISP's resolvers.

Before You Start

Have the following ready before opening the admin panel:

• Router access: A device connected to the Mercusys network — wired connection preferred for stability during changes.
• Admin password: Set during initial router setup. The default username is admin. If you have forgotten the password, hold the reset button on the back of the router for 8 to 10 seconds to factory-reset it, then reconfigure from scratch.
• Chosen DNS servers: Decide which servers to use before logging in. Options are covered in the section below.
• Supported models: This guide applies to the MR30G, MR70X, MS60, MR20, MW305R, AC1200, and AC1900 series. The admin UI is consistent across all current Mercusys firmware. Older single-band models on firmware 1.x have a slightly different menu layout but identical underlying settings.

Step 1 — Log Into the Mercusys Admin Panel

Open a browser and navigate to http://192.168.1.1. This is the default gateway IP for all current Mercusys routers. If that page does not load, try http://192.168.0.1 — a minority of older units shipped on the 192.168.0.x subnet. A small number of early Mercusys devices (primarily the MW305R on its original firmware) used http://melogin.cn as a branded admin URL, though Mercusys has phased this out in favour of direct IP access in all recent firmware generations.

Log in with username admin and your configured password. If the router displays the setup wizard instead of the main dashboard, complete it first — DNS settings are only accessible after basic WAN configuration has been saved.

Step 2 — Change DNS in WAN Settings

This is the primary DNS configuration. It controls what servers the router queries when it performs upstream resolution on behalf of your network. The path to reach these settings depends on your firmware generation:

1. In the left navigation panel, click Network.
2. Select WAN (firmware 1.x) or Internet (firmware 2.x and later).
3. Scroll to the DNS section. The default reads Get DNS server address dynamically from ISP.
4. Uncheck or toggle that option off. Manual DNS input fields appear below it.
5. Enter your chosen resolver in Primary DNS Server and a backup in Secondary DNS Server.
6. Click Save. The change takes effect immediately without a reboot.

Step 3 — Override DHCP DNS to Reach Every Client

Step 2 sets what the router uses internally. Step 3 ensures every client device on your LAN receives the correct DNS addresses via DHCP lease. If you skip this step, devices that were previously assigned DNS addresses directly by your ISP may continue using those values until their DHCP lease expires or is manually renewed.

1. Navigate to Network → DHCP Server.
2. Find the Primary DNS and Secondary DNS fields in the address pool settings.
3. Enter the same DNS servers used in Step 2. Consistent values across WAN and DHCP avoids split-resolution where the router resolves differently from its own clients.
4. Click Save.

Force existing devices to pick up the new DNS without waiting for their lease to expire naturally:

DNS Server Options Worth Using

Not all resolvers perform equally. These four are the most reliable choices in 2026:

• Cloudflare — 1.1.1.1 / 1.0.0.1: Fastest resolver globally across most independent latency benchmarks. Privacy-first policy with no sale of query data. Anycast infrastructure across 300-plus cities, with DNSSEC validation enabled by default.
• Google Public DNS — 8.8.8.8 / 8.8.4.4: Extremely reliable, in continuous operation since 2009. Google documents its privacy practices including a 24 to 48 hour debug log retention window. Wide Anycast coverage keeps latency low from most regions.
• Quad9 — 9.9.9.9 / 149.112.112.112: Actively blocks malware and phishing domains using threat intelligence from over 20 partners. A practical default for home networks with children or small offices where endpoint security software is thin.
• OpenDNS — 208.67.222.222 / 208.67.220.220: Cisco-owned resolver with configurable category-based content filtering. Meaningful per-category filtering requires linking your public IP to a free OpenDNS Home account.

For most homes: Cloudflare (1.1.1.1) as primary, Google (8.8.8.8) as secondary. Cross-provider secondaries mean your fallback runs on completely separate infrastructure if either provider has an incident.

How to Verify the DNS Change Worked

After saving, test from a client device on your network to confirm DNS is resolving through the new servers:

If the Server field in nslookup still shows your ISP's DNS IP, the DHCP lease on that device has not yet renewed. Run the release and renew commands from Step 3. If it shows 192.168.1.1 (the router's LAN IP), that is normal and correct — the router is acting as a local forwarder and proxying queries upstream through the DNS you configured.

Troubleshooting Common Problems

DNS Settings Revert After a Router Reboot

This indicates a flash write failure — settings appeared to save but were not committed to NVRAM before power was removed. Re-enter your DNS values, click Save, then reboot using System Tools → Reboot (or Advanced → System → Reboot) from inside the admin panel rather than pulling the power cable. A graceful shutdown gives the firmware time to complete the write. If the problem recurs on the same unit, perform a full factory reset, reconfigure from scratch, and immediately export a configuration backup via System Tools → Backup & Restore → Backup before the next reboot.

Some Devices Still Use Old DNS

Devices configured with static IP addresses or manually set DNS entries will ignore DHCP-pushed DNS completely. Check each problem device individually. On Windows: Settings → Network & Internet → [adapter] → DNS → set to Automatic. On iPhone: Settings → Wi-Fi → tap your network → Configure DNS → Automatic. On Android: Settings → Network → Wi-Fi → long-press your network → Modify Network → Advanced → IP settings → DHCP (not Static).

melogin.cn No Longer Loads After the DNS Change

This is expected, not a failure. The melogin.cn hostname resolved through Mercusys's own DNS infrastructure to the router's local gateway IP. After switching to Cloudflare or Google as your resolver, that private DNS record is no longer reachable. Use http://192.168.1.1 directly to access the admin panel — this always works regardless of which upstream DNS servers are configured.

Specific Domains Resolve Slowly After Switching

A freshly switched resolver starts with a cold cache for domains your household queries regularly. This warmup period is transient — most records carry TTLs of 300 to 3600 seconds, and the cache fills within minutes of normal browsing. If slowness on a particular domain persists beyond an hour, the upstream resolver may have degraded routing to that zone's authoritative nameservers. Swap the secondary to a different provider as a diagnostic step.

Common Misdiagnoses

Several problems are frequently blamed on the DNS change when the actual cause is something else entirely:

• Internet stops working after saving DNS: Almost always a typo in the DNS IP field. Verify the address digit by digit, then try navigating directly to 1.1.1.1 in the browser. If that loads a Cloudflare page, your internet connection is fine and the DNS value you entered is wrong.
• Device still shows old DNS after the router change: Almost always a DHCP lease that has not yet expired. Run the lease renewal commands in Step 3 before escalating the diagnosis further.
• Sites that loaded before now return errors: Some ISPs intercept NXDOMAIN responses and redirect misspelled or nonexistent domains to a branded search page. After switching to a legitimate resolver, those redirects stop and you see a real NXDOMAIN error. This is correct behaviour — the previous ISP DNS was masking resolution failures with a redirect.
• Changing only WAN DNS, or only DHCP DNS: Changing only WAN DNS sets what the router uses for its own upstream queries but may not affect clients depending on how they are configured. Changing only DHCP DNS pushes addresses to clients but does not fix how the router itself resolves. Set both as described in Steps 2 and 3 to eliminate ambiguity.

2026 Notes — IPv6 DNS, DoH, and DNSSEC on Mercusys

Current Mercusys firmware through mid-2026 does not support DNS-over-HTTPS or DNS-over-TLS at the router level. Queries between your devices and the router's LAN interface use standard UDP port 53, and queries from the router to upstream resolvers are also unencrypted. This is a common limitation across consumer routers in this price category and is not unique to Mercusys.

On dual-stack IPv4 and IPv6 networks, client devices may resolve DNS over IPv6 and bypass your IPv4 DNS configuration entirely. If your Mercusys firmware includes an IPv6 section (Network → IPv6), configure IPv6 DNS addresses explicitly alongside your IPv4 entries:

For encrypted DNS without waiting on Mercusys firmware support, enable DoH at the OS or browser level on individual devices. Windows 11 supports encrypted DNS natively: Settings → Network & Internet → [adapter] → DNS server assignment → Edit → Encrypted only (DNS over HTTPS). Chrome exposes DoH under Settings → Privacy and security → Use secure DNS. Firefox has an equivalent under Settings → Privacy & Security → Enable DNS over HTTPS. These operate independently of whatever the router is doing with upstream DNS.

DNSSEC signature validation is not performed locally by Mercusys firmware. However, both Cloudflare (1.1.1.1) and Google (8.8.8.8) validate DNSSEC signatures at their resolvers on your behalf, meaning signed zones are protected against cache poisoning even without router-level validation.

Preventing Settings from Reverting

• Export a config backup immediately after saving your DNS changes. Navigate to System Tools → Backup & Restore → Backup and save the .bin file to your computer. Restoring from it after a factory reset or firmware wipe takes under a minute and brings back all your settings at once.
• Review auto-update behaviour: Major Mercusys firmware updates occasionally reset WAN settings on install. Go to System Tools → Firmware Upgrade and confirm whether automatic updates are enabled. Set it to manual if configuration stability matters more than automatically receiving firmware releases.
• Document your DNS server IPs alongside your Wi-Fi password somewhere accessible. After a power outage or accidental reset, having the values on hand removes the temptation to skip reconfiguring DNS and leave ISP defaults in place.
• Temporarily lower DHCP lease time when making DNS changes if you need all devices to adopt the new settings quickly. Set Network → DHCP Server → Lease Time to 3600 seconds (one hour), wait for devices to renew, then restore the default of 86400 seconds (24 hours) once the rollout is confirmed across your network.