DNS Proxy Service

DNS Proxy Service is a simple DNS proxy server that runs as a Windows service. The service listens for DNS queries from DNS clients and forwards them to the DNS servers configured on the local system.

Notable features

• Automatic and manual DNS listen address configuration
• IPv4, IPv6 and DNSSEC support
• Event logging (Windows Application event log)
• Responsive to IP address and DNS server address changes (including laptop computers moving to another wifi network)

Installation

• Install the Microsoft .NET 8 Runtime (Microsoft.NETCore.App)
• Run DnsProxySetup.msi (see release assets)

Configuration

By default DNS Proxy Service automatically provides DNS service on IPv4 addresses associated with Hyper-V NAT networks. Automatic configuration requires the Hyper-V optional Windows feature.

DNS Proxy Service can also provide DNS service on manually configured IPv4/IPv6 addresses (except for loopback, multicast and IPv6 link/site local addresses). Manual configuration does not require Hyper-V.

Automatic configuration and manual configuration can be combined.

The default settings in appsettings.json can be overridden in appsettings.Production.json in the same folder. Do not modify appsettings.json itself. The following settings can be configured:

• DnsProxy:Listen. An array of IPv4/IPv6 addresses on which to listen for DNS queries. The special value Auto (default) enables automatic configuration for Hyper-V NAT networks.

• DnsProxy:QueryTimeout. The timeout in milliseconds for forwarded DNS queries (range: 1000-10000, default: 5000).

• DnsProxy:ServerStartMaxTries. The maximum number of attempts to start DNS service on a new IP address (range: 1-10, default: 5). In rare cases an IP address may not yet be ready for use when it is discovered causing DNS service start on the IP address to fail. DNS Proxy Service will retry if this happens.

• DnsProxy:ServerStartRetryDelay. The time in milliseconds between attempts to start DNS service on a new IP address (range: 1000-10000, default: 2000).

• Logging:EventLog:LogLevel:DnsProxy. The logging level for messages written to the Windows Application event log (default: Information).

You must restart DNS Proxy Service after modifying appsettings.Production.json.

Build tools

DNS Proxy Service was developed using Visual Studio 2022. The HeatWave extension is required to build the setup package.