How To • VPN Basics and Conflicts • DNS Troubleshooting

How to Fix DNS Issues Caused by VPN Software

This guide will help you diagnose and resolve common problems where a VPN prevents websites from loading, slows down browsing, or leaks your DNS requests. You will learn to check for DNS leaks, adjust VPN settings, and configure your system's DNS for reliable, private browsing while the VPN is active.

We'll cover steps for your computer, VPN application, and router to ensure a complete fix.

Note: Steps may vary by device and router model. This guide focuses on safe, general methods.

Quick Answer

Disconnect from the VPN and test your normal internet connection first.
Open your VPN app's settings and enable features like "DNS leak protection" or "Use VPN's DNS."
Manually set your device's DNS to a public provider (like Cloudflare's 1.1.1.1 or Google's 8.8.8.8).
Flush your computer's DNS cache to clear outdated address records.
Try switching the VPN protocol (e.g., from OpenVPN to WireGuard) in the app settings.
Restart your VPN software and reconnect to a different server.

If this doesn't work, use the diagnostic flow below to pinpoint the exact cause.

What you need

Before you start

A working internet connection without the VPN.
Access to your VPN software and account.
Administrator or root access to your computer.
Basic knowledge of how to open network settings on your OS.
Patience to test after each change.

Good to know

DNS translates website names (like luvvhelp.com) to IP addresses.
VPNs often route your DNS queries through their own private servers.
If this DNS routing fails, websites won't load even with a VPN connection.
Some ISPs or networks may block common VPN protocols.
Your VPN's kill switch can sometimes interfere with DNS.
IPv6 can sometimes cause DNS leaks if the VPN doesn't support it.

Diagnose the issue in 2 minutes

Step 1: Is the problem only with the VPN?
- Disconnect the VPN. Can you browse normally? If No, your base internet or router has an issue.
- If Yes, reconnect the VPN and continue.
Step 2: What is the exact symptom with VPN on?
- "This site can't be reached" or "DNS_PROBE_FINISHED_BAD_CONFIG": Likely a DNS failure. Go to Step 3.
- Extremely slow browsing but connection exists: Could be slow VPN DNS servers or a congested server.
- Some sites work, others don't: Specific sites may be blocking your VPN's IP address.
Step 3: Perform a DNS leak test.
- With VPN connected, search for "DNS leak test" in your browser.
- Run the standard test. The results should show servers owned by your VPN provider, not your ISP or local network.
- If you see your ISP's DNS servers, you have a DNS leak.
Step 4: Check VPN connection stability.
- Open a command line/terminal. Type ping 8.8.8.8 (Google's public DNS IP).
- If you get steady replies, your VPN tunnel works but DNS is broken.
- If ping fails or has high packet loss, the VPN connection itself is unstable.

Step-by-step guide

Step 1 — Verify your baseline connection

Ensure the problem is isolated to the VPN and not your underlying network.

Completely disconnect from your VPN service.
Open a browser and visit several common websites (e.g., a search engine, a news site).
If browsing works fine, the issue is with the VPN. If not, troubleshoot your basic internet connection first.

Step 2 — Check VPN DNS settings

Your VPN app likely has built-in DNS controls. Enabling protection features is the first fix.

Open your VPN application and navigate to its Settings or Preferences.
Look for a section labeled "DNS," "Privacy," or "Network."
Enable options such as "DNS Leak Protection," "Use VPN's DNS," or "Block non-VPN DNS."
If available, select a specific DNS server like "Private DNS" or "Ad-blocking DNS."

What you should see: The setting toggled to "On." After reconnecting, test browsing again.

Step 3 — Flush your local DNS cache

Your computer stores old DNS records. Flushing clears this cache and forces it to fetch new, correct addresses through the VPN.

Windows: Open Command Prompt as Administrator. Type ipconfig /flushdns and press Enter.

macOS: Open Terminal. Type sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder and press Enter (you'll need your password).

Linux: The command varies. For systems using systemd-resolved, open Terminal and type sudo systemd-resolve --flush-caches.

Step 4 — Manually configure device DNS

Bypass automatic DNS assignment by setting a reliable public DNS server on your device's network adapter.

Go to your operating system's Network Settings.
Find the active connection (Wi-Fi or Ethernet). Click on its properties or advanced settings.
Locate the "DNS" settings and change it from "Automatic" to "Manual."
Add the DNS server addresses: 1.1.1.1 (Cloudflare) and 8.8.8.8 (Google).
Save changes and reconnect the VPN.

Step 5 — Change VPN protocol

Some protocols handle network changes and DNS more reliably than others.

In your VPN app settings, find the "Protocol" or "Connection" section.
Switch from your current protocol (e.g., OpenVPN) to a different one (e.g., WireGuard or IKEv2).
Reconnect to the VPN. Test if DNS resolution improves.

What you should see: A potentially more stable connection and faster DNS lookups.

Step 6 — Disable IPv6 temporarily

If your VPN does not fully support IPv6, DNS queries may leak via the IPv6 protocol.

Go to your OS network settings for your main adapter (Wi-Fi/Ethernet).
Find the properties for "Internet Protocol Version 6 (TCP/IPv6)."
Uncheck the box to disable it.
Apply changes. Some VPN apps also have an option to "Disable IPv6" within their settings.

Step 7 — Test on a different VPN server

The specific server you're connected to may have malfunctioning DNS resolvers.

In your VPN app, disconnect from your current server.
Choose a server in a different city or country.
Reconnect and test your browsing and a DNS leak test again.

Step 8 — Router-level consideration

If you run VPN software on your router, or if issues persist, check router DNS.

Access your router's admin panel (often via 192.168.1.1 in a browser).
Navigate to WAN or Internet settings.
Ensure DNS is set to "Obtain Automatically from ISP" or manually set to public DNS (1.1.1.1).
Save and reboot the router.

When to stop: This is a broader change affecting all devices. Only proceed if you're comfortable with router configuration.

Common fixes by symptom

Symptom: "Connected to VPN but no websites load"

Likely causes: DNS server unreachable, VPN kill switch blocking all traffic, incorrect protocol.

Disable the VPN's kill switch feature temporarily to test.
Manually set device DNS to 1.1.1.1.
Flush DNS cache (see Step 3).

Escalate if: Pinging 8.8.8.8 also fails—this indicates a full tunnel break, not just DNS.

Symptom: Very slow browsing with VPN on

Likely causes: Congested VPN server, slow VPN-provided DNS servers, distance to server.

Switch to a less crowded VPN server or one closer to you.
Change VPN protocol to a faster one like WireGuard.
Set your device DNS to a fast public resolver (Cloudflare, Google).

Escalate if: Speeds are equally slow without VPN—contact your ISP.

Symptom: DNS leak (test shows your ISP's DNS)

Likely causes: IPv6 leak, VPN app bug, operating system overriding DNS.

Enable "DNS leak protection" in the VPN app.
Disable IPv6 on your network adapter.
Ensure your firewall isn't interfering with the VPN client.

Escalate if: Leak persists across multiple servers and app reinstalls—consider a different VPN provider.

Symptom: Some specific websites don't work

Likely causes: Website blocking VPN IP ranges, DNS-based filtering, or geo-restrictions.

Try connecting to a VPN server in a different country.
Use your browser in private/incognito mode to rule out local cache.
Temporarily try a different public DNS provider.

Escalate if: The site is critical and no VPN server works—you may need to disconnect VPN for that specific task.

Symptom: Internet drops when VPN connects/disconnects

Likely causes: Aggressive kill switch, DNS cache corruption, network stack conflict.

Adjust kill switch settings to be less restrictive.
Flush DNS cache and reboot your computer.
Run the VPN app as administrator (Windows).

Escalate if: Issue causes persistent loss of all connectivity—a network reset may be needed.

Symptom: Can't access local network devices (NAS, printer) with VPN on

Likely causes: VPN routing all traffic, including local addresses, through the remote tunnel.

Look for a "Split Tunneling" setting in your VPN app.
Add your local IP range (e.g., 192.168.1.0/24) to the exclusion list.
Alternatively, disable the VPN when you need local access.

Escalate if: Your VPN lacks split tunneling features and local access is essential.

Quick reference

Table A: What the metric means

Metric	What it tells you about your VPN/DNS
Latency (Ping)	Delay to a server. High ping with VPN indicates a distant or overloaded server, which can slow DNS queries.
Jitter	Variation in latency. High jitter can cause intermittent DNS timeouts and unstable browsing.
Packet Loss	Data packets that don't arrive. Even 1-2% loss can break DNS lookups and page loading.
Throughput	Actual download/upload speed. A fast throughput but slow browsing points to a DNS issue, not bandwidth.
Signal Strength (Wi-Fi)	Weak signal can cause VPN disconnections, leading to DNS failures when the kill switch activates.

Table B: Safe baseline settings

Category	Recommended Setting for VPN Use
Device DNS	Set to automatic when VPN is off. Consider manual (1.1.1.1) if VPN DNS fails.
VPN DNS	Enable "DNS leak protection" and "Use VPN's DNS servers."
IPv6	Disable on your device's network adapter if your VPN has leak issues.
Firewall	Ensure your VPN app is allowed through firewall/antivirus software.
Router DNS	Set to obtain automatically or use a neutral public DNS; avoid ISP DNS here.

Mind map summary

VPN DNS Issue
├── Diagnosis
│   ├── Test without VPN (Baseline OK?)
│   ├── Run DNS Leak Test (ISP shown?)
│   └── Ping 8.8.8.8 (Tunnel alive?)
├── Quick Fixes (App Level)
│   ├── Enable "DNS Leak Protection"
│   ├── Switch VPN Protocol (Try WireGuard)
│   └── Connect to Different Server
├── Device-Level Fixes
│   ├── Flush Local DNS Cache
│   ├── Manually Set DNS to 1.1.1.1
│   └── Disable IPv6 on Adapter
├── Advanced/System
│   ├── Check Firewall/VPN App Permissions
│   ├── Configure Split Tunneling (for local access)
│   └── Review Router DNS Settings
└── Last Resort
    ├── Reinstall VPN Software
    ├── Network Stack Reset (OS specific)
    └── Contact VPN Support / Consider Alternative Provider

Troubleshooting checklist

Device

Flushed DNS cache
Manually set public DNS (1.1.1.1)
Disabled IPv6 on network adapter
Allowed VPN app in firewall
Restarted the device

VPN Application

DNS leak protection enabled
Changed connection protocol
Toggled kill switch off/on
Connected to different server
Updated to latest app version
Reinstalled the VPN app

Network & ISP

Confirmed base internet works (VPN off)
Tested on another network (e.g., mobile hotspot)
Checked router DNS settings
Verified no ISP-level VPN blocking

When to escalate

Contact your VPN provider support

If you've tried all app and device-level fixes and still experience persistent DNS leaks, constant disconnections, or inability to connect to any server. They have logs and server-side insights.

Consider a different VPN service

If your current provider consistently has slow DNS servers, lacks essential features like leak protection or modern protocols, and support is unhelpful.

Consult IT support or a networking professional

If the issue affects multiple users on a business network, involves complex router-based VPNs, or if you suspect deep system corruption.

What to collect before escalating

Screenshots of DNS leak test results.
Your VPN app version and protocol used.
Timestamps of when the issue occurs.
Specific error messages from your browser or VPN app.
Results of ping 8.8.8.8 and tracert 8.8.8.8 with VPN on and off.

FAQ

What is a DNS leak and why is it bad?

A DNS leak occurs when your DNS queries are sent to your Internet Service Provider's servers (or another third party) instead of through your VPN's encrypted tunnel. This defeats a major purpose of a VPN: privacy.

Even though your IP address is hidden, the DNS requests can reveal what websites you are trying to visit.

Should I use my VPN's DNS or a public one like Cloudflare?

It's generally best to use your VPN's DNS servers when connected. They are designed to work with their network and often include privacy promises. However, if your VPN's DNS is slow or unreliable, manually switching to a reputable public DNS can be a good troubleshooting step and permanent fix for speed.

Can antivirus or firewall software cause VPN DNS problems?

Yes. Security software sometimes includes its own DNS filtering or network inspection features that can intercept and reroute DNS queries, bypassing the VPN. Try temporarily disabling these features (or adding an exception for your VPN app) to test.

Why does my internet work fine but some apps can't connect with VPN on?

Some applications (like games, financial software, or certain messaging apps) use hard-coded DNS or make direct IP connections that might be blocked or misrouted by the VPN. This is where "Split Tunneling" is useful—you can exclude those specific apps from the VPN tunnel.

What's the difference between a DNS issue and a general VPN connection issue?

If you have a general connection issue, you likely can't ping external IP addresses (like 8.8.8.8) and have no data flow. A DNS-specific issue means you can ping IP addresses successfully, but you cannot resolve website names (like google.com). The latter allows some VPN-connected apps that use IPs to work, while browsing fails.

How often should I flush my DNS cache?

Only when you're experiencing problems like being unable to access a website that you know is online, or after changing your DNS settings. It's a troubleshooting step, not a regular maintenance task.

Does using a VPN on my phone cause the same DNS issues?

Yes, the same principles apply on mobile devices (iOS/Android). Mobile VPN apps have similar DNS settings. You can also configure manual DNS on your phone's Wi-Fi settings, though it's less common. Always check for DNS leak tests using a mobile browser.

What is "Split Tunneling" and how can it help?

Split Tunneling lets you choose which apps or IP addresses go through the VPN tunnel and which use your regular internet connection. You can use it to exclude local network devices or bandwidth-heavy apps from the VPN, which can sometimes resolve routing and DNS conflicts for those specific services.

Sources and references

Microsoft Windows Documentation: Network Shell (netsh) commands and TCP/IP reset procedures.
Apple Support Documentation: macOS Network Utility and DNS configuration guides.
Linux Manual Pages: systemd-resolved, NetworkManager, and ip-route command references.
VPN Provider Knowledge Bases: Common articles on DNS leak protection and connection troubleshooting.
IEEE 802.11 Standards Overview: Underlying concepts of wireless networking that affect VPN stability.
IETF RFCs on DNS (Domain Name System) protocol operation and security extensions (DNSSEC).
General networking guides on ICMP (Ping, Traceroute) for diagnostic purposes.
Cybersecurity best practices for VPN usage and DNS privacy.

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How to fix DNS issues caused by VPN software

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