Manage rules for Azure Load Balancer using the Azure portal

Azure Load Balancer supports rules to configure traffic to the backend pool. In this article, you learn how to manage the rules for an Azure Load Balancer.

There are four types of rules:

• Load-balancing rules - A load balancer rule is used to define how incoming traffic is distributed to all the instances within the backend pool. A load-balancing rule maps a given frontend IP configuration and port to multiple backend IP addresses and ports. An example would be a rule created on port 80 to load balance web traffic.

• High availability ports - A load balancer rule configured with protocol - all and port - 0. These rules enable a single rule to load-balance all TCP and UDP traffic that arrive on all ports of an internal standard load balancer. The HA ports load-balancing rules help with scenarios, such as high availability and scale for network virtual appliances (NVAs) inside virtual networks. The feature can help when a large number of ports must be load-balanced.

• Inbound NAT rule - An inbound NAT rule forwards incoming traffic sent to frontend IP address and port combination. The traffic is sent to a specific virtual machine or instance in the backend pool. Port forwarding is done by the same hash-based distribution as load balancing.

• Outbound rule - An outbound rule configures outbound Network Address Translation (NAT) for all virtual machines or instances identified by the backend pool. This rule enables instances in the backend to communicate (outbound) to the internet or other endpoints.

Prerequisites

• An Azure account with an active subscription. Create an account for free.

• A standard public load balancer in your subscription. For more information on creating an Azure Load Balancer, see Quickstart: Create a public load balancer to load balance VMs using the Azure portal. The load balancer name for the public examples in this article is myPublicLoadBalancer.

• A standard internal load balancer in your subscription. For more information on creating an Azure Load Balancer, see Quickstart: Create an internal load balancer to load balance VMs using the Azure portal. The load balancer name for the internal examples in this article is myInternalLoadBalancer.

The public and internal load balancers are separate resources. Each procedure in this article states which one to select.

To open any load balancer used in this article, sign in to the Azure portal, enter Load balancer in the search box at the top of the portal, select Load balancers in the search results, and then select the load balancer named in that procedure.

Load-balancing rules

In this section, you learn how to add and remove a load-balancing rule. A public load balancer is used in the examples.

Add a load-balancing rule

In this example, you create a rule to load balance port 80 on the public load balancer.

1. Open myPublicLoadBalancer in the Azure portal.

2. In the load balancer page, select Load balancing rules in Settings.

3. Select + Add in Load balancing rules to add a rule.

4. Enter or select the following information in Add load balancing rule.

   Setting	Value
   Name	myHTTPRule
   IP Version	Select IPv4 or IPv6.
   Frontend IP address	Select the frontend IP address of the load balancer. In this example, it's myFrontendIP.
   Protocol	Leave the default of TCP.
   Port	Enter 80.
   Backend port	Enter 80.
   Backend pool	Select the backend pool of the load balancer. In this example, it's myBackendPool.
   Health probe	Select Create new. In Name, enter myHealthProbe. Select HTTP in Protocol. Leave the rest at the defaults or tailor to your requirements. Select OK.
   Session persistence	Select None or your required persistence. For more information about distribution modes, see Azure Load Balancer distribution modes.
   Idle timeout (minutes)	Leave the default of 4 or move the slider to your required idle timeout.
   TCP reset	Select Enabled. For more information on TCP reset, see Load Balancer TCP Reset and Idle Timeout.
   Floating IP	Leave the default of Disabled or enable if your deployment requires floating IP. For information on floating IP, see Azure Load Balancer Floating IP configuration.
   Outbound source network address translation (SNAT)	Leave the default of (Recommended) Use outbound rules to provide backend pool members access to the internet. For more information on outbound rules and (SNAT), see Outbound rules Azure Load Balancer and Using Source Network Address Translation (SNAT) for outbound connections.

5. Select Add.

6. Confirm that myHTTPRule appears in the Load balancing rules list. Select Health status, and then select View details to confirm that the health probe reports your backend instances as healthy. Traffic reaches the backend pool only when at least one instance is healthy.

Remove a load-balancing rule

In this example, you remove a load-balancing rule.

1. Open myPublicLoadBalancer in the Azure portal.

2. In the load balancer page, select Load balancing rules in Settings.

3. Select the three dots next to the rule you want to remove.

4. Select Delete.

5. Confirm that the rule no longer appears in the Load balancing rules list.

High availability ports

In this section, you learn how to add and remove a high availability ports rule. You use an internal load balancer in this example.

HA ports rules are supported on a standard internal load balancer.

Add high availability ports rule

In this example, you create a high-availability ports rule on the internal load balancer.

1. Open myInternalLoadBalancer in the Azure portal.

2. In the load balancer page, select Load balancing rules in Settings.

3. Select + Add in Load balancing rules to add a rule.

4. Enter or select the following information in Add load balancing rule.

   Setting	Value
   Name	Enter myHARule.
   IP Version	Select IPv4 or IPv6.
   Frontend IP address	Select the frontend IP address of the load balancer. In this example, it's myFrontendIP. Select the box next to HA Ports.
   Backend pool	Select the backend pool of the load balancer. In this example, it's myBackendPool.
   Health probe	Select Create new. In Name, enter myHealthProbe. Select TCP in Protocol. Enter a TCP port in Port. In this example, it's port 80. Enter a port that meets your requirements. Leave the rest at the defaults or tailor to your requirements. Select OK.
   Session persistence	Select None or your required persistence. For more information about distribution modes, see Azure Load Balancer distribution modes.
   Idle timeout (minutes)	Leave the default of 4 or move the slider to your required idle timeout.
   TCP reset	Select Enabled. For more information on TCP reset, see Load Balancer TCP Reset and Idle Timeout.
   Floating IP	Leave the default of Disabled or enable if your deployment requires floating IP. For information on floating IP, see Azure Load Balancer Floating IP configuration.

   For more information on HA ports rule configuration, see High availability ports overview.

5. Select Add.

6. Confirm that myHARule appears in the Load balancing rules list and shows HA Ports as the port configuration.

Remove a high availability ports rule

In this example, you remove a high availability ports rule.

1. Open myInternalLoadBalancer in the Azure portal.

2. In the load balancer page, select Load balancing rules in Settings.

3. Select the three dots next to the rule you want to remove.

4. Select Delete.

5. Confirm that the rule no longer appears in the Load balancing rules list.

Inbound NAT rule

Inbound NAT rules are used to route connections to a specific VM in the backend pool. For more information and a detailed tutorial on configuring and testing inbound NAT rules, see Tutorial: Configure port forwarding in Azure Load Balancer using the portal.

Outbound rule

You learn how to add and remove an outbound rule in this section. You use a public load balancer in this example.

Outbound rules are supported on standard public load balancers.

Add outbound rule

In this example, you create an outbound rule on the public load balancer.

1. Open myPublicLoadBalancer in the Azure portal.

2. In the load balancer page, select Outbound rules in Settings.

3. Select + Add in Outbound rules to add a rule.

4. Enter or select the following information in Add outbound rule.

   Setting	Value
   Name	Enter myOutboundRule.
   IP Version	Select IPv4 or IPv6.
   Frontend IP address	Select the frontend IP address of the load balancer. In this example, it's myFrontendIP.
   Protocol	Leave the default of All.
   Idle timeout (minutes)	Leave the default of 4 or move the slider to meet your requirements.
   TCP Reset	Leave the default of Enabled.
   Backend pool	Select the backend pool of the load balancer. In this example, it's myBackendPool.
   Port allocation
   Port allocation	Select Manually choose number of outbound ports.
   Outbound ports
   Choose by	Select Ports per instance.
   Ports per instance	Enter 10000.

5. Select Add.

6. Confirm that myOutboundRule appears in the Outbound rules list with the port allocation you selected.

Remove an outbound rule

In this example, you remove an outbound rule.

1. Open myPublicLoadBalancer in the Azure portal.

2. In the load balancer page, select Outbound rules in Settings.

3. Select the three dots next to the rule you want to remove.

4. Select Delete.

5. Confirm that the rule no longer appears in the Outbound rules list. Backend instances lose the outbound connectivity that rule provided unless another outbound path exists.

Next steps

In this article, you learned how to manage load-balancing rules for an Azure Load Balancer.

For more information about Azure Load Balancer, see:

• What is Azure Load Balancer?
• Frequently asked questions - Azure Load Balancer