# Configure a NLB

Select the NLB element to open its properties in the Inspector pane on the right. The name of the NLB and the number of balanced [<mark style="color:blue;">NICs</mark>](https://docs.ionos.com/support/general-information/glossary-of-terms#nic) are displayed at the top of the pane.

Configuration options are grouped under three tabs: [<mark style="color:blue;">**Settings**</mark>](#settings), [<mark style="color:blue;">**Forwarding rules**</mark>](#forwarding-rules), and [<mark style="color:blue;">**Private IPs**</mark>](#private-ips).

![Configuration of a network load balancer](https://1737632334-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MifAzdGvKLDTtvJP8sm%2Fuploads%2Fgit-blob-130082bfde95e4d4f623e60409075df71dd06955%2Fconfig_settings.png?alt=media)

### **Settings**

NLB Listener accepts connections from clients through an exposed [<mark style="color:blue;">IP address</mark>](https://docs.ionos.com/support/general-information/glossary-of-terms#ip-address) (**Primary IPv4**) and configured listener port. The Listener interface can also monitor additional IPs (**Add IP**). Listener IPs can be **private** (for local networks) or **public** (exposed to the Internet). Public IPs must be reserved before they can be used. For more information, see [<mark style="color:blue;">**Listener**</mark>](https://docs.ionos.com/cloud/managed-services/network-load-balancer/outline#listener).

You can fill in the following details in **Settings:**

* **Name**: You can use the default or enter a new name for the NLB.
* By clicking on **Load Balancer** you can show or hide the **Primary IPv4** and **Add IP** settings.
* **Primary IPv4**: Assign the first (primary) Listener IP address. For **Automatic**, no entry is required; a private primary Listener IP address will be assigned automatically on provisioning.
* For private IP, enter a private IP address directly. For public IP, Public IP is required for an NLB that is connected to the Internet.

{% hint style="info" %}
Public IPs must first be reserved. Reserve public IPs using the **IP Manager** in the main menu.
{% endhint %}

* **Add IP**: Assign one or more additional Listener IPs; additional IPs are optional. For private IP, choose **Add private IP** and enter the address directly.
* **Reserve public IP**: Available only when no reserved public IPs exist. Click **Add IP** > **Reserve public IP**, enter a name for the IP block, the number of IPs to be reserved, and click **Reserve IPs**.
* **Public IP**: Public IPs must already have been reserved. Click **Add IP** and choose a reserved IP block name from the drop-down list, then select a reserved IP address.
* **Multiple IPs**: Use **Add IP** again to add as many IPs as needed. All added private and public IPs are listed below the IP settings.

{% hint style="info" %}
Configuration changes are saved only once the VDC is [<mark style="color:blue;">provisioned</mark>](https://docs.ionos.com/cloud/managed-services/network-load-balancer/setup-nlb#provisioning-a-new-nlb).
{% endhint %}

### Forwarding rules

Forwarding rules define how client traffic is distributed to the targets. More than one forwarding rule can be created for the same load balancer.

In **Forwarding rules**, you can enter a name for this forwarding rule, choose a load balancing algorithm from the drop-down list, set the protocol to TCP (it cannot be changed), select an IP address for **Listener IP**, enter the Listener port directly, or select one from the list.

#### **Create a rule**

* Click **Create** to create the rule.
* Click the name of the rule to expand or collapse its settings.
* Click **Add target** to add targets.
* Choose **Health check** to configure Health check connection settings for this forwarding rule.
* Use **Add forwarding rule** again to add as many rules as needed. All added rules are listed in Inspector under the Forwarding rules tab.

### **Private IPs**

NLB backend exposes a private IP to targets as the source of client traffic. The backend IP address is configurable and defaults to x.x.x.225. **Backend IPs** are listed in the NLB Inspector under the Private IPs tab.

#### **Adding and deleting IPs**

* It is best to use the default IP address in most cases. To change an already-provisioned IP, delete the existing IP address first and then add a new one.
* Click the down arrow and select **Remove IP** to delete the IP address.
* Enter an IP address *in CIDR notation* (e.g. 10.10.10.225/24), and click **Add IP**. The new IP must be private and match the subnet mask of the Target network.
* Use **Add IP** again to add as many private IPs as needed. All added IPs are listed under the **Private IPs**.