Bug ID 726015: On Windows 10, DNS resolution does not work for queries made to IPv6 DNS server if VPN is established and DNS relay proxy is running.

Last Modified: Apr 28, 2025

Affected Product(s):
APM-Clients TMOS(all modules)

Known Affected Versions:
7.1.6, 7.1.6.1, 7.1.7, 7.1.7.1, 7.1.7.2, 7.1.8, 7.1.8.1, 7.1.8.2, 7.1.8.3, 7.1.8.4, 7.1.8.5, 7.1.9, 7.1.9.7, 7.1.9.8, 7.1.9.9

Opened: Jun 27, 2018

Severity: 3-Major

Symptoms

When VPN is established, and the DNS relay proxy is running on Windows 10, the DNS resolution does not work for queries made to the IPv6 DNS server.

Impact

- DNS resolution does not work.

Conditions

- Windows 10. - DNS Relay Proxy Service is running. - IPV6 DNS server specified in Network Access Settings

Workaround

There are 2 workarounds: 1. Add the following key: HKLM\SOFTWARE\Policies\Microsoft\Windows NT\DnsClient -Set DWORD "EnableMultiHomedRouteConflicts" to 0 (zero). This workaround restores Windows DNS client behavior to pre-Windows 10 where this is not an issue. 2. Specify IPv4 DNS server as well in the Network Access configuration.

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips