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Basic Configuration

This section will cover a basic LiteSpeed Web ADC configuration using a LiteSpeed Web ADC server as well as two (or more) web servers running on separate machines from one another. For simplicity, we will be assuming the following setup:

  • Two web servers
  • LiteSpeed Web ADC configured to handle HTTP traffic
  • A single site being hosted on both of the servers


If you would like to use LiteSpeed Web ADC for a different application, simply replace clusterHTTP in this guide with the appropriate cluster type (AJP,LSAPI,FCGI,MIX).

Initial Setup

To start, log into your LiteSpeed Web ADC WebAdmin Console using the IP address of your LiteSpeed Web ADC server and the port number you assigned the LiteSpeed Web ADC WebAdmin Console during installation. We will be using as our LiteSpeed Web ADC IP address and the default port 7090 for the LiteSpeed Web ADC WebAdmin Console.

Create a Cluster

Once you have logged in, navigate to Configuration > Clusters and click Add at the top right of Clusters List.

First, you will be asked what Type of cluster you wish to create. Choose Layer 7 and click Next.

Choose a cluster type

On the next screen, fill in the details for the new cluster, like so:

Define a new cluster

  • Cluster Name: clusterXYZ (or whatever you would like to call it)
  • Mode: Stateful
  • Strategy: Least Load
  • Session Extraction: check the following
    • IP Address
    • Query String
    • Cookies
    • SSL Session
  • Session ID String: phpsessid
  • Session Timeout: 600
  • Insert Tracking Cookie: Yes
  • Tracking Cookie Name: lslb_backend

Click Save at the top right.

Create a Worker Group

Now that you have a cluster defined, you can define a worker group, and add in your two web servers as nodes. For this example we will be using and as our two web servers and ports. Replace these values with the IP addresses and ports of your own web servers.

Click clusterXYZ to view the cluster, and click the tab for Worker Group. Then click Add, and define the worker group as follows:

Define a new worker group

  • Name: xyzHTTP
  • Type: HTTP Proxy
  • Enabled: Yes
  • Max Connections: 20
  • Initial Request Timeout (secs): 60
  • Retry Timeout (secs): 0
  • Node Address List:(**Node1**)>, (**Node2**)>

Leave all other options set to the default values.


Node Address List is a comma-separated list in the following format:

If you are using IPv6, the IP must be surrounded by [].

Click Save at the top right.

Create a Virtual Host

With your cluster fully configured, and your web servers added as nodes to a worker group in said cluster, it's time to create a LiteSpeed Web ADC virtual host.

Navigate to Configuration > Virtual Hosts.


Since you will be creating our own virtual host, you no longer need the provided "Example" host. If you'd like to delete it, you can click Delete in the Action section for that host, and then click Yes to confirm.

Click Add at the top right of the Virtual Host List, and define a new virtual host, like so:

Create a virtual host

  • Virtual Host Name: vHost-1
  • Default Cluster: clusterXYZ
  • Configure File: $SERVER_ROOT/conf/vhost-1.xml

Click Save at the top right.

Create a Listener

Now that we have a LiteSpeed Web ADC virtual host configured, the final step is to set a listener for that virtual host.

Navigate to Configuration > Listeners


You may already have a "Default" listener configured and mapped to the "Example" virtual host. If this is the case, you don't need to Add a new listener. You can simply Edit the Default listener and delete it's virtual host mapping to Example.

Click Add at the top right of the Listeners list.

Select Type HTTP (Layer 7) and click Next. Create a new listener with the following values:

Add a listener

  • Listener Name - Default
  • Port - 80
  • Secure - No

Leave the rest of the settings at their default values, and click Save at the top right.

You will be sent back to the listener list. Click Default. to view the listener we just added.

Since we created our own LiteSpeed Web ADC Virtual host earlier (vHost-1), we can now add a new mapping. Click Add in the Virtual Host Mappings section, and create a mapping with the following values:

Map a vhost to the listener

  • Virtual Host: vHost-1
  • Domains: *

Click Save at the top right.

Apply all of the changes with a graceful restart. Navigate to Actions > Graceful Restart and click the OK button when asked Are you sure you want to restart server?.

Your LiteSpeed Web ADC should now be working and ready to handle all incoming HTTP traffic to your specified port/site!


Below are two methods of testing that LiteSpeed Web ADC is configured correctly and working. We will again be assuming you have two web servers with LiteSpeed Web ADC handling HTTP requests to a web site hosted on both of these servers.


These tests can both be modified to test other applications of LiteSpeed Web ADC.

For both tests: Run your servers in an isolated environment (no outside traffic), and make a small but noticeable change to the home page on one of your web servers. This is done so that you can easily tell which web server fills the request.

Test 1: Disable a Server

Aside from balancing your servers' traffic to avoid a crash, one of the main features of a load balancer is to appropriately redirect traffic to an available server if another server should experience a failure. With two servers running this is an easy thing to check.

To begin, visit your site through a browser. Make note of which server you are being directed to by noticing the presence or absence of the small change you made earlier. We will call this server "Server 1". If your Mode is set to Stateful under Load Balancer Definition in Configuration > Clusters > clusterXYZ (as it will be if you followed the tutorial above), then Server 1 will be the preferred server for LiteSpeed Web ADC to direct your IP address to. This is known as "Session Affinity".

Now that we know which server you are being directed to, either stop Server 1 or change Server 1's port to a number LiteSpeed Web ADC is not aware of, and restart it. If everything is working correctly, the next time you attempt to visit your site, LiteSpeed Web ADC will instead redirect your request to Server 2, which you can again confirm with respect to the small change made earlier.

Test 2: Round Robin

From the LiteSpeed Web ADC WebAdmin Console, navigate to Configuration > Clusters. Select clusterXYZ, or whatever cluster you are using to direct HTTP traffic. Click Edit at the top right of the Load Balancer Definition section.

Change Mode to Stateless and Strategy to Round Robin.

Edit load balancer definition

Click Save at the top right.

By choosing Stateless, you have told LiteSpeed Web ADC to ignore "Session Affinity" for this cluster. Meaning that you are equally likely to be sent to Server 1 or Server 2 on an HTTP request for your site. By choosing Round Robin, you have told LiteSpeed Web ADC to rotate back and forth between Server 1 and Server 2 when receiving HTTP requests for your site.

Perform a Graceful Restart to have the new definition take effect.


Because of possible browser caching, this next part is best done through the terminal.

Use the following terminal command to request your web page. For this example our domain name is Replace this with your own domain name or the IP address and port of your LSLB server.

curl -i


curl -i

Run this command a few times to check if LiteSpeed Web ADC is correctly swapping back and forth between Server 1 and Server 2 by checking for the small change made earlier. The output should be similar to Server 1, then Server 2, then Server 1, then Server 2, and so on.


It is recommended to set Mode and Strategy back to your previous settings when done performing this test. The default settings are Stateful and Least Load respectively.


You can use QUIC on LiteSpeed Web ADC if the following are true:

  • QUIC is enabled in the WebAdmin Console (it is enabled by default)
  • The browser supports QUIC and has QUIC enabled
  • You are not using a self-signed certificate
  • You are not using a proxy front end like CloudFlare

Create Secure Listener

  • Navigate to WebAdmin Console > Configuration > Listeners and press the Add button.
  • Choose HTTP (Layer 7) then press the Next button.
  • Set Listener Name to LS-443 or your choice of name.
  • Set Port to 443.
  • Set Secure to Yes.
  • Press the Save button.

Configure SSL

  • Back at the Server Listeners list, select LS-443.
  • Select the SSL tab.
  • Click Edit in the SSL Private Key & Certificate section.
  • Set Private Key File, Certificate File and CA Certificate File to your certificate file location.
  • Press the Save button.

Enable QUIC

QUIC is enabled in Web ADC by default. If it has been turned off, and you need to enable it manually, this is how:

  • While still viewing LS-443, scroll down to Security Features and click Edit
  • Set Allow QUIC to Yes.
  • Press the Save button.

Enable QUIC

Configure Firewall

QUIC (Quick UDP Internet Connections) runs a stream-multiplexing protocol over Transport Layer Security (TLS) on top of UDP instead of TCP. Be sure you've enabled the port with both TCP and UDP.

How to verify QUIC is enabled

You can test your own site, or any site on the Internet, with the free HTTP/3 Check tool. Enter a URL, and HTTP/3 Check will tell you whether QUIC or HTTP/3 are supported by that site. Detailed connection information, including HTTP header and QLOG output are provided as well. (Please check out our video tutorial, if needed.)

Another option is the HTTP Indicator extension for Chrome or Mozilla. It displays a lightning bolt in the Chrome toolbar. Blue indicates HTTP/2 is enabled, and orange indicates HTTP/3. Alternatively, you can hover over the lightning bolt to see a tool tip that displays the protocol in use.


You should see the appropriate indicator on dynamic pages with a regular refresh. If not, press CTRL + SHIFT + R to request a fresh copy of the page.

HTTP Indicator

Turning On the Debug Log

To turn on the Web ADC Debug Log, you would follow the exact same steps that are laid-out here for LiteSpeed Web Server.

See Also

This document covers the basics, but you will probably also want to configure these more specialized areas:

And more.

Last update: February 9, 2024