VPN Breaks Your Connection on Windows 11? DNS Leaks and Adapter Priority

3 Aug 2026
VPN Breaks Your Connection on Windows 11? DNS Leaks and Adapter Priority

Virtual Private Networks (VPNs) have become essential for secure remote working, protecting sensitive business data and accessing internal company resources. However, if enabling your VPN suddenly causes websites to stop loading, Microsoft Teams to disconnect or network drives to disappear, the VPN itself may not actually be the problem.

On Windows 11, connectivity issues after connecting to a VPN are often caused by DNS configuration, network adapter priority or routing conflicts, rather than the encrypted tunnel itself.

Understanding how Windows decides where network traffic should go can help you resolve the issue without abandoning your VPN.

What Happens When You Connect to a VPN?

When a VPN connects successfully, Windows creates a new virtual network adapter.

Instead of sending traffic directly through your Wi-Fi or Ethernet connection, Windows routes selected or all traffic through this secure encrypted tunnel.

During this process Windows may also:

  • Change your DNS servers
  • Add new network routes
  • Modify adapter priority
  • Redirect default internet traffic
  • Apply security policies
  • Create new firewall rules

If any of these settings become incorrect or conflict with existing network settings, internet access may appear to stop completely.

Common Symptoms

Users often report:

  • Connected to the VPN but no internet access
  • Internal company resources unavailable
  • Websites refusing to load
  • Microsoft Teams disconnecting
  • Outlook unable to connect
  • Network drives disappearing
  • File shares inaccessible
  • Slow browsing after connecting
  • DNS errors
  • Certain websites working while others fail

These symptoms usually point towards routing or name resolution rather than the VPN connection failing entirely.

Understanding DNS

DNS (Domain Name System) converts website names into IP addresses.

For example:

www.microsoft.com

becomes an IP address your computer can communicate with.

If DNS fails, your internet connection may still be working perfectly—you simply cannot find the destinations you are trying to reach.

This is why you may see:

  • VPN connected
  • Excellent Wi-Fi signal
  • No websites loading

The network is functioning.

The name resolution is not.

What Is a DNS Leak?

A DNS leak occurs when DNS requests bypass the VPN tunnel and are instead sent to your normal internet provider or another DNS server.

This creates two problems:

Privacy

Your internet provider can still see which websites your device is requesting.

Reliability

Internal company servers may only be resolvable using the DNS servers supplied through the VPN.

If Windows sends requests elsewhere, addresses such as:

fileserver

or

intranet.company.local

may never resolve correctly.

The VPN appears broken when, in reality, Windows is simply asking the wrong DNS server.

Signs of a DNS Problem

You may notice:

  • Websites load by IP address but not by name.
  • Internal servers cannot be found.
  • Network drives disappear.
  • Remote Desktop cannot locate host names.
  • Ping works with IP addresses but not hostnames.
  • Outlook cannot locate Exchange services.
  • Teams signs out repeatedly.

These symptoms strongly suggest DNS rather than internet failure.

Flush the DNS Cache

Windows stores recently resolved addresses.

Occasionally these become outdated.

Open Command Prompt as Administrator and run:

ipconfig /flushdns

Then reconnect the VPN.

This forces Windows to request fresh DNS information.

Renew Your Network Configuration

Sometimes Windows continues using previous network settings after switching between networks.

Run:

ipconfig /release

Followed by:

ipconfig /renew

This refreshes your network configuration.

Check Which DNS Servers Are Being Used

Open Command Prompt and run:

ipconfig /all

Look for:

  • VPN adapter
  • Wi-Fi adapter
  • Ethernet adapter

Check which DNS servers each adapter is using.

If your company VPN should provide internal DNS servers but Windows is still using your broadband provider’s DNS, internal resources may never resolve correctly.

Test Name Resolution

Use:

nslookup

For example:

nslookup google.com

or

nslookup fileserver

The output shows which DNS server answered the request.

If the wrong server is responding, the VPN configuration should be investigated.

Understanding Adapter Priority

Windows can have several active network adapters simultaneously:

  • Ethernet
  • Wi-Fi
  • VPN
  • Hyper-V virtual switches
  • VMware adapters
  • VirtualBox adapters
  • WSL networking
  • Bluetooth networking

Windows decides which one to use based partly on interface metrics, often referred to as adapter priority.

If the wrong adapter has higher priority, Windows may send traffic outside the VPN instead of through it.

Signs of Incorrect Adapter Priority

Typical symptoms include:

  • VPN connects but internet fails.
  • Some websites work.
  • Company resources fail.
  • Network drives disconnect.
  • Internal applications cannot communicate.
  • Split tunnelling behaves incorrectly.

The VPN is functioning.

Windows is simply choosing the wrong route.

Check Interface Metrics

Open PowerShell and run:

Get-NetIPInterface

This displays interface metrics.

Lower numbers generally have higher priority.

If your VPN adapter has a much higher metric than your physical network adapter, Windows may not route traffic as expected.

Many VPN clients manage this automatically, but older software or manual configurations can introduce problems.

Split Tunnelling Explained

Many businesses use split tunnelling.

Instead of routing everything through the VPN, only company traffic travels through the encrypted tunnel.

Everything else continues using your local internet connection.

Benefits include:

  • Better internet performance
  • Lower VPN bandwidth usage
  • Reduced latency
  • Improved video conferencing performance

However, incorrect split tunnel routes can lead to:

  • Internal resources unavailable
  • Websites loading inconsistently
  • Incorrect DNS behaviour
  • Traffic bypassing the VPN unexpectedly

Review split tunnel policies carefully if connectivity problems occur only for certain destinations.

Check the Routing Table

Windows keeps a routing table that determines where every packet is sent.

Open Command Prompt and run:

route print

Look for:

  • Duplicate routes
  • Unexpected default gateways
  • Incorrect VPN routes
  • Multiple active gateways

If several VPN clients have been installed over time, outdated routes can sometimes remain.

Multiple VPN Clients

Having more than one VPN client installed can create conflicts.

Examples include:

  • Cisco AnyConnect
  • GlobalProtect
  • FortiClient
  • Sophos Connect
  • OpenVPN
  • WireGuard
  • Microsoft Always On VPN

Each installs virtual adapters and routing components.

Even when not actively connected, remnants of previous VPN software may interfere with networking.

If you’ve changed VPN providers recently, remove unused VPN software completely.

Windows Firewall

Some VPN software automatically adjusts Windows Firewall rules.

If these become corrupted:

  • Websites may fail.
  • Internal servers become unreachable.
  • DNS requests may be blocked.
  • Applications lose connectivity.

Review firewall rules if problems begin immediately after installing new VPN software.

IPv6 Considerations

Some VPN providers tunnel IPv4 traffic only.

Meanwhile Windows continues using IPv6 where available.

This can create inconsistent behaviour.

For troubleshooting purposes, temporarily testing with IPv6 disabled can help determine whether routing conflicts are involved.

If disabling IPv6 resolves the issue, investigate whether your VPN client fully supports IPv6 rather than leaving it permanently disabled without good reason.

Update Network Drivers

Outdated drivers can affect:

  • VPN stability
  • DNS behaviour
  • Adapter priority
  • Packet handling
  • Sleep and wake reliability

Check for updates to:

  • Wi-Fi drivers
  • Ethernet drivers
  • VPN client software
  • Network chipset drivers
  • VPN virtual adapter drivers

Use drivers supplied by the PC manufacturer wherever possible.

Reset the Windows Network Stack

If multiple settings have become corrupted, Windows can rebuild its networking configuration.

Open Settings → Network & Internet → Advanced network settings → Network reset

This reinstalls network adapters and resets networking components.

Afterwards you may need to reconnect Wi-Fi networks and reinstall VPN software if required.

When the VPN Software Is Actually the Problem

Sometimes the VPN application itself requires attention.

Consider:

  • Updating the VPN client
  • Removing and reinstalling it
  • Checking certificate validity
  • Reviewing authentication logs
  • Testing another VPN protocol
  • Confirming your subscription or licence is active

Many modern VPN clients release regular updates to improve compatibility with Windows 11 feature updates.

Avoid Common “Fixes” That Create More Problems

Some online advice recommends:

  • Permanently disabling IPv6
  • Turning off Windows Firewall
  • Disabling Microsoft Defender
  • Removing all DNS servers manually
  • Editing the registry without understanding the changes

These may temporarily hide the symptoms while reducing your computer’s security or causing additional networking problems.

Diagnose the root cause before making permanent changes.

A Simple Troubleshooting Checklist

If your VPN breaks your connection:

  1. Confirm the VPN connected successfully.
  2. Test whether websites open using IP addresses.
  3. Flush the DNS cache.
  4. Check which DNS servers Windows is using.
  5. Run nslookup.
  6. Review adapter metrics.
  7. Examine the routing table.
  8. Check split tunnel settings.
  9. Update VPN software and network drivers.
  10. Reset networking if corruption is suspected.

Working through these steps methodically is far more effective than changing multiple settings at random.

How Hamilton Group Can Help

Reliable VPN connectivity is critical for businesses that depend on remote working, secure access to company resources and Microsoft 365.

At Hamilton Group, we diagnose VPN connectivity issues, investigate DNS problems, resolve routing conflicts and optimise Windows networking for secure hybrid working. Whether your employees are working from home, travelling or connecting between multiple offices, we can ensure your VPN remains secure, stable and reliable.

Our services include:

  • VPN deployment and support
  • DNS troubleshooting
  • Network diagnostics
  • Microsoft 365 connectivity
  • Remote working solutions
  • Firewall configuration
  • Secure networking
  • Windows 11 support
  • Device management
  • Ongoing managed IT support

Restore Your Connection Without Compromising Security

A VPN that breaks your internet connection is rarely caused by encryption itself.

More often, Windows is using the wrong DNS server, selecting the wrong network adapter or following an incorrect routing table.

By checking DNS, adapter priority and routing before making major configuration changes, you can usually restore reliable connectivity while keeping the security benefits of your VPN.

If your Windows 11 PC loses connectivity whenever you connect to a VPN, contact Hamilton Group on 0330 043 0069. Our experts can identify the root cause and get your secure connection working properly again.


 

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