Configure TCP reset and idle timeout for Azure Load Balancer

Azure Load Balancer rules have a default timeout range of 4 minutes to 100 minutes for Load Balancer rules, Outbound Rules, and Inbound NAT rules. The default setting is 4 minutes. If a period of inactivity is longer than the timeout value, there's no guarantee that the TCP or HTTP session is maintained between the client and your service.

The following sections describe how to change idle timeout and tcp reset settings for load balancer resources.

Set tcp reset and idle timeout

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Portal

To set the idle timeout and tcp reset for a load balancer, edit the load-balanced rule.

1. Sign in to the Azure portal.
2. In the left-hand menu, select Resource groups.
3. Select the resource group for your load balancer. In this example, the resource group is named myResourceGroup.
4. Select your load balancer. In this example, the load balancer is named myLoadBalancer.
5. In Settings, select Load balancing rules.
6. Select your load-balancing rule. In this example, the load-balancing rule is named myLBrule.
7. In the load-balancing rule, input your timeout value into Idle timeout (minutes).
8. Under TCP reset, select Enabled.
9. Select Save.

PowerShell

To set the idle timeout and tcp reset, set values in the following load-balancing rule parameters with Set-AzLoadBalancer:

• IdleTimeoutInMinutes
• EnableTcpReset

If you choose to install and use PowerShell locally, this article requires the Azure PowerShell module version 5.4.1 or later. Run Get-Module -ListAvailable Az to find the installed version. If you need to upgrade, see Install Azure PowerShell module. If you're running PowerShell locally, you also need to run Connect-AzAccount to create a connection with Azure.

Replace the following examples with the values from your resources:

• myResourceGroup
• myLoadBalancer

$lb = Get-AzLoadBalancer -Name "myLoadBalancer" -ResourceGroup "myResourceGroup"
$lb.LoadBalancingRules[0].IdleTimeoutInMinutes = '15'
$lb.LoadBalancingRules[0].EnableTcpReset = 'true'
Set-AzLoadBalancer -LoadBalancer $lb

Azure CLI

To set the idle timeout and tcp reset, use the following parameters for az network lb rule update:

• --idle-timeout
• --enable-tcp-reset

Validate your environment before you begin:

• Sign in to the Azure portal and check that your subscription is active by running az login.
• Check your version of the Azure CLI in a terminal or command window by running az --version. For the latest version, see the latest release notes.
  • If you don't have the latest version, update your installation by following the installation guide for your operating system or platform.

Replace the following examples with the values from your resources:

• myResourceGroup
• myLoadBalancer
• myLBrule

az network lb rule update \
    --resource-group myResourceGroup \
    --name myLBrule \
    --lb-name myLoadBalancer \
    --idle-timeout 15 \
    --enable-tcp-reset true

Next steps

For more information on tcp idle timeout and reset, see Load Balancer TCP Reset and Idle Timeout

For more information on configuring the load balancer distribution mode, see Configure a load balancer distribution mode.