What this page covers
Run repeatable, local diagnostics and do not treat changing DNS providers as a universal fix.
Step-by-step workflow
- Test the gateway, a known IP and a hostname separately.
- Use nslookup or dig against the configured resolver.
- Compare wired/Wi-Fi and one alternate authorised client.
- Record timeout, SERVFAIL, NXDOMAIN or refusal results.
Decision table
| Check | What it tells you | Safe next action |
|---|---|---|
| IP works, name fails | Resolution path is the likely branch | Inspect resolver and cache |
| Only some names fail | Authoritative or policy issue may exist | Compare response codes |
| Everything drops | DNS may be a symptom, not the cause | Check link and gateway |
Limits and verification
A public DNS change can hide a local DHCP or security problem. Preserve the original configuration and verify the cause.
Official sources
- Microsoft — Troubleshoot DNS server issues (DNS diagnosis)
- IETF RFC 8415 — DHCP for IPv6 (DHCPv6 behavior)
Related Router Portal guides
Router login troubleshooting · Find the current gateway
Keep in mind: Firmware, operating-system menus, ISP policies and regional radio rules can change. Confirm the current official source and exact device before applying a setting.
Our networking steps are lab-tested against standard RFC 1918 private networking protocols across Windows 11 (24H2), macOS Sequoia (15.1), iOS 18, and Android 15. We verify physical device labels and firmware release documentation before publishing gateway instructions. Router Portal is strictly read-only and never requests, intercepts, or logs router passwords.