Network Management

Using the Force-Enable Multi-Subnet Failover Option in the Configuration Wizard

When configuring a SolarWinds product with the Configuration Wizard, you may encounter a Force-enable multi-subnet failover checkbox on the database connection page. This article explains what this setting does, when to enable it, and what to expect.

First published date

10/21/2026 7:40 AM

Last published date

10/21/2026 7:40 AM

Overview

Enabling the Force-enable multi-subnet failover checkbox adds MultiSubnetFailover=True to the database connection string, regardless of whether the Configuration Wizard automatically detects an Always On Availability Group (AG) or Failover Cluster Instance (FCI) in your environment.

This property is part of Microsoft's SqlClient library and is designed to improve connection behavior when SQL Server is configured for high availability and disaster recovery.

When should you enable this setting?

Enable the Force-enable multi-subnet failover option if your SQL Server environment uses any of the following:

  • Always On Availability Groups (AGs)

  • Always On Failover Cluster Instances (FCIs)

You should specify MultiSubnetFailover=True whenever you are connecting to the FCI or the listener of an AG. This setting enables faster failover for all AGs and FCIs in SQL Server 2012 or later, and significantly reduces failover time for both single-subnet and multi-subnet Always On topologies.

Note: Do not enable this setting if you are not using an AG or FCI. Specifying MultiSubnetFailover=True when connecting to a standard SQL Server instance (not an AG or FCI) may result in negative performance impact and is not supported.

How does MultiSubnetFailover improve performance?

When MultiSubnetFailover=True is set in the connection string:

  • During a multi-subnet failover, the client attempts connections to all IP addresses in parallel rather than sequentially, reducing the time it takes to reconnect.

  • During a single-subnet failover, the client aggressively retries the TCP connection faster than the operating system's default TCP retransmit intervals.

  • The client targets the primary SQL Server instance by attempting all associated IP addresses simultaneously, so a successful connection is established as quickly as possible.

This behavior applies to both single-subnet and multi-subnet AG and FCI configurations.

Product section

Orion Platform

Resolution

Connection guidelines for Always On environments

Use the following best practices when connecting SolarWinds to an Always On-enabled SQL Server:

  • Use MultiSubnetFailover=True for both single-subnet and multi-subnet configurations; it improves performance in both cases.

  • Specify the availability group listener as the server name in your connection string when connecting to an AG — do not specify an individual replica.

  • Do not connect to a SQL Server instance configured with more than 64 IP addresses, as this will cause a connection failure.

  • Authentication type (SQL Server Authentication, Kerberos, or Windows Authentication) does not affect the behavior of MultiSubnetFailover.

  • Consider increasing the Connect Timeout value to accommodate the time required for a failover event and to reduce retry attempts.

  • Distributed transactions are not supported in AG environments.

.NET Framework version considerations

If your environment uses .NET Framework 4.6.1 or later, setting MultiSubnetFailover=True is not strictly required for that framework version. However, it is required for .NET Core and .NET 5 or later. Enabling the checkbox ensures the connection string is explicitly set regardless of the framework version detected.