Resolving DNS Server Override Issues During VPN Connections on Windows 7 Active Directory Networks


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When establishing VPN connections from Windows 7 clients in Active Directory environments, we often encounter DNS resolution problems that disrupt access to local network resources. The fundamental issue occurs because Windows prioritizes the VPN adapter's DNS settings over the physical network interface's configuration.

The problematic behavior manifests when:

  • DFS namespace paths suddenly become inaccessible (\\dfsroot\share)
  • Folder redirection policies fail (AppData, Desktop, etc.)
  • Domain authentication issues emerge
  • Local resource access breaks while remote access works

From the ipconfig outputs, we observe:

DNS Servers . . . . . . . . . . . : 192.168.0.16
                                 192.168.0.17

Despite manually configuring the PPTP connection to prefer local DNS servers (10.58.3.32), Windows persists in using the remote DNS servers for all queries.

Option 1: Registry Modification (Persistent Fix)

Create a registry script to modify DNS prioritization:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
"InterfacePriorityMetric"=dword:00000001
"SkipInterfacePriorityMetricUpdate"=dword:00000001
"DNSQueryOrdering"=dword:00000001

Option 2: PowerShell DNS Cache Management

Run this script after VPN connection establishes:

# Clear DNS cache
Clear-DnsClientCache

# Set DNS server priority
Set-DnsClientServerAddress -InterfaceIndex (Get-NetAdapter -Name "Local Area Connection").ifIndex -ServerAddresses ("10.58.3.32","10.58.3.33")

# Force DNS registration
Register-DnsClient

Option 3: Connection-Specific DNS Suffixes

Configure the VPN connection properties to:

  1. Uncheck "Use default gateway on remote network"
  2. Set "Use these DNS servers" to your local DNS servers
  3. Add connection-specific DNS suffix: mydomain.local

For immediate relief with DFS issues, add entries to the hosts file:

10.58.3.32    dfsroot.mydomain.local
10.58.3.32    mydomain.local
10.58.3.32    domaincontroller.mydomain.local

For domain-wide deployment, create a GPO with these settings:

Computer Configuration > Policies > Administrative Templates > Network > DNS Client:
- Configure Connection-Specific DNS Suffixes: Enabled
- Primary DNS Suffix Devolution: Disabled
- Register PTR Records: Disabled

Use these commands to verify DNS resolution paths:

nslookup dfsroot.mydomain.local
Resolve-DnsName dfsroot.mydomain.local -Type A -DnsOnly
Get-DnsClientCache | Where-Object {$_.Entry -like "*mydomain*"}

When establishing a VPN connection to a client's network from a Windows 7 machine in our Active Directory domain, we encountered a critical issue where all DNS queries were being routed through the remote DNS servers (192.168.0.16/17) instead of our local DNS servers (10.58.3.32/33). This caused:

  • Disappearing network shares (including DFS roots)
  • Broken folder redirection (Application Data, Desktop, etc.)
  • Inaccessible domain resources

Our network configuration:

Local network: 10.58.5.0/24 (part of 10.58.0.0/16)
Remote network: 192.168.0.0/24
Local DNS servers: 10.58.3.32, 10.58.3.33
Remote DNS servers: 192.168.0.16, 192.168.0.17

The routing table shows proper network segmentation, but DNS resolution fails for local resources when VPN is active.

Windows prioritizes DNS servers based on interface metrics. The VPN connection's DNS servers were taking precedence over local DNS servers, even when:

  • Not configured as default gateway
  • Explicit DNS server order was specified in PPTP settings
  • Local interface had higher binding order priority

1. Registry Modification for DNS Priority

Create a .reg file with the following content:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Linkage]
"Route"=hex(7):44,00,65,00,76,00,69,00,63,00,65,00,5c,00,4e,00,65,00,74,00,42,\
  00,54,00,5c,00,54,00,63,00,70,00,69,00,70,00,5f,00,7b,00,46,00,30,00,34,00,\
  44,00,41,00,32,00,44,00,42,00,33,00,42,00,43,00,41,00,7d,00,00,00,44,00,65,\
  00,76,00,69,00,63,00,65,00,5c,00,50,00,50,00,50,00,30,00,5f,00,7b,00,43,00,\
  75,00,73,00,74,00,6f,00,6d,00,65,00,72,00,44,00,6f,00,6d,00,61,00,69,00,6e,\
  00,7d,00,00,00,00,00

Replace the GUIDs with your actual interface GUIDs from Device Manager.

2. PowerShell Script for DNS Management

Run this script after VPN connection:

# Get all network interfaces
$adapters = Get-NetAdapter | Where-Object {$_.Status -eq "Up"}

# Set DNS server priority
foreach ($adapter in $adapters) {
    if ($adapter.InterfaceDescription -like "*CustomerDomain*") {
        Set-DnsClientServerAddress -InterfaceIndex $adapter.InterfaceIndex 
            -ServerAddresses ("10.58.3.32","10.58.3.33","192.168.0.16","192.168.0.17")
    }
    else {
        Set-DnsClientServerAddress -InterfaceIndex $adapter.InterfaceIndex 
            -ServerAddresses ("10.58.3.32","10.58.3.33")
    }
}

# Force DNS client service restart
Restart-Service dnscache

3. Advanced Solution: NRPT Rules

For enterprise environments, create Name Resolution Policy Table rules:

# Create NRPT rule for local domain
Add-DnsClientNrptRule -Namespace "mydomain.local" 
    -NameServers "10.58.3.32","10.58.3.33"

# Verify rules
Get-DnsClientNrptPolicy

For immediate relief with DFS issues, add to hosts file:

# Append to C:\Windows\System32\drivers\etc\hosts
10.58.3.32    dfsroot.mydomain.local
10.58.3.32    mydomain.local

After implementing solutions, verify with:

nslookup mydomain.local
nslookup dfsroot.mydomain.local
nslookup customerdomain.com

Each query should resolve through the appropriate DNS servers.