Full Diagnostic Tree & Step-by-Step Overview
Open your terminal or Command Prompt (`cmd`). Run `ping 1.1.1.1`. Does the ping receive successful replies, even though web browsers show 'DNS Server Not Responding' when visiting websites?
- Ping to 1.1.1.1 is SUCCESSFUL (0% loss), but domain names fail to load
- Ping to 1.1.1.1 FAILS (100% packet loss / Request timed out)
- The issue occurs on ONLY ONE browser (e.g., Chrome works, but Edge fails)
Have you flushed the local OS DNS resolver cache or changed your network adapter DNS settings yet?
- No, I haven't flushed the cache or touched network adapter DNS settings
- I already flushed DNS, but domains still refuse to resolve
Corrupted OS DNS Cache Table or Locked Winsock Catalog
Solution:
Diagnostic Cause
The Windows DNS Client service caches domain-to-IP lookup results locally to speed up browsing. If an IP address changes or a bad record gets cached, your computer attempts to send requests to non-responsive or stale endpoints.
Step-by-Step Fix
1. Open Command Prompt as Administrator (Win + X > *Terminal/CMD (Admin)*).
2. Execute the following commands in exact sequential order, pressing Enter after each:
ipconfig /flushdns *(Purges local lookup cache)*ipconfig /registerdns *(Forces dynamic registration of DNS names/IPs)*ipconfig /release *(Releases active IPv4 lease)*ipconfig /renew *(Requests fresh DHCP configuration from router)*netsh winsock reset *(Resets Windows socket API catalog to defaults)*3. Restart your computer and test website access.
Is your network adapter set to 'Obtain DNS server address automatically' (using your ISP's local DNS), or are you using static custom DNS addresses?
- Set to 'Automatic' (Using ISP DNS default)
- Already configured with custom static DNS (e.g., 1.1.1.1 or 8.8.8.8)
ISP DNS Server Outage / Unresponsive Upstream Forwarder
Solution:
Diagnostic Cause
Most home networks route DNS queries through the Internet Service Provider's default DNS servers via the router gateway. ISP DNS infrastructure frequently suffers from overload, packet drops, or routing deadlocks.
Step-by-Step Fix
1. Press Win + R, type ncpa.cpl, and press Enter to open Network Connections.
2. Right-click your active network connection (Wi-Fi or Ethernet) > select Properties.
3. Select Internet Protocol Version 4 (TCP/IPv4) > click Properties.
4. Select Use the following DNS server addresses:
Preferred DNS server: 1.1.1.1 (Cloudflare)Alternate DNS server: 8.8.8.8 (Google Public DNS)5. Check Validate settings upon exit and click OK.
*(Optional macOS Instructions: System Settings > Network > Active Adapter > Advanced > DNS tab > Click '+' and add 1.1.1.1 and 8.8.8.8)*.
Are you using a Virtual Private Network (VPN), third-party antivirus with 'Web Shield', or is IPv6 active on your network interface?
- IPv6 is enabled on my network adapter alongside IPv4
- I have an active VPN, firewall, or antivirus web protection module running
- Neither; custom DNS is set, no VPN is active, but resolution still fails
IPv6 DNS Query Timeout / Broken IPv6 Tunnel Route
Solution:
Diagnostic Cause
When IPv6 is enabled, Windows prioritizes IPv6 DNS resolution (AAAA records) over IPv4 (A records). If your router or ISP advertises an IPv6 route but fails to resolve IPv6 DNS queries, system lookups hang until timing out.
Step-by-Step Fix
1. Press Win + R, type ncpa.cpl, and press Enter.
2. Right-click your active network connection > select Properties.
3. Method A (Assign Public IPv6 DNS):
Select Internet Protocol Version 6 (TCP/IPv6) > click Properties.Select Use the following DNS server addresses:Preferred: 2606:4700:4700::1111 (Cloudflare IPv6)Alternate: 2001:4860:4860::8888 (Google IPv6)4. Method B (Disable IPv6 Stack if unsupported by ISP):
Uncheck the box next to Internet Protocol Version 6 (TCP/IPv6) in the properties list.Click OK to save and force all queries over healthy IPv4 routes.
Antivirus SSL/DNS Filtering Driver Hooking Failure
Solution:
Diagnostic Cause
Security suites (e.g., Avast Real-Site, AVG, Bitdefender) and VPN clients install virtual network filter drivers that intercept port 53 UDP traffic. When these filter services crash internally, all outbound DNS queries are blackholed.
Step-by-Step Fix
1. Temporarily disable your third-party Antivirus Web Shield or Real-Time Protection module.
2. Disconnect and fully exit any installed VPN software (e.g., NordVPN, ExpressVPN, WireGuard client).
3. Open Device Manager (Win + X > *Device Manager*) > expand Network adapters.
4. If any yellow warning icons appear next to virtual adapters (e.g., *TAP-Windows Adapter*), right-click and select Disable device, wait 5 seconds, then select Enable device.
Windows OS Binding Order Glitch Across Multiple Adapters
Solution:
Diagnostic Cause
In Windows 10/11, 'Smart Multi-Homed Name Resolution' sends DNS queries across ALL available network interfaces (Wi-Fi, Ethernet, Cellular) simultaneously and accepts the fastest response. If one secondary interface responds with an error, it can lock down lookups.
Step-by-Step Fix
1. Press Win + R, type gpedit.msc, and hit Enter *(Windows Pro/Enterprise)*.
2. Navigate to: Computer Configuration > Administrative Templates > Network > DNS Client.
3. Double-click Turn off smart multi-homed name resolution.
4. Select Enabled (this turns OFF the problematic multi-homed behavior).
5. Click Apply > OK.
6. Open CMD as Admin and execute gpupdate /force.
Browser Application-Level Secure DNS Conflict
Solution:
Diagnostic Cause
Modern web browsers (Chrome, Edge, Firefox) bypass system-level OS DNS settings by default using built-in DNS-over-HTTPS (DoH). If the browser's designated DoH provider experiences a service interruption, system DNS fixes will not restore browser browsing.
Step-by-Step Fix
1. Open your browser settings:
Chrome/Edge: Settings > Privacy and Security > Security > Scroll to Use Secure DNS.Firefox: Settings > Privacy & Security > Scroll down to DNS over HTTPS.2. Temporarily set Secure DNS mode to Off (or change provider to *Cloudflare 1.1.1.1*).
3. In your browser address bar, clear internal DNS host cache:
Chrome: Navigate to chrome://net-internals/#dns > Click Clear host cache.Edge: Navigate to edge://net-internals/#dns > Click Clear host cache.
Since pinging raw IP addresses (1.1.1.1) fails, your entire internet data connection is severed. Is this issue occurring across ALL connected devices (phones, TVs, PCs) on the same Wi-Fi/Ethernet network?
- Yes, ALL devices on the network have lost internet/DNS connectivity
- No, other devices work fine; ONLY THIS device fails raw IP ping
Router Gateway DNS Proxy Service Crash / Memory Leak
Solution:
Diagnostic Cause
Home routers run embedded Linux DNS proxy services (such as dnsmasq). When the router's DNS proxy crashes or encounters an upstream lease loss from the ISP modem, it stops responding to port 53 UDP queries from all connected LAN devices.
Step-by-Step Fix
1. Unplug the power cables from BOTH your router and standalone modem.
2. Wait 60 full seconds to dump volatile SRAM/RAM DNS tables.
3. Plug the modem in first and wait until all signal LEDs (DS/US/Online) solidify.
4. Plug the router back in and allow 2 minutes to initialize.
5. If the issue recurs frequently, log into your router's web dashboard (192.168.1.1 or 192.168.0.1), navigate to WAN/Internet Settings, and change the router's WAN DNS servers from 'Auto/ISP' directly to 1.1.1.1 and 8.8.8.8.
Corrupted Device Driver Stack / Hardware Interface Failure
Solution:
Step-by-Step Fix
1. Press Win + X and select Device Manager.
2. Expand Network adapters.
3. Right-click your active Wi-Fi or Ethernet adapter (e.g., *Intel Ethernet Controller* or *Realtek Wi-Fi Adapter*) > select Uninstall device.
4. Check the box Attempt to remove the driver for this device (if available) > click Uninstall.
5. Click Action on the top menu bar > select Scan for hardware changes.
6. Windows will detect the physical network card and re-initialize a completely fresh default driver stack.