# License clients and license servers

Understanding the concept of "**license client**" and "**license server**" is essential for a correct setup.

<div id="bkmrk-the-%22license-client%22">- The "[license client](https://lhc.advantest.com/books/client-configuration-and-license-management "License configuration and license management on a license client provide you with the tools and utilities to help you to administer licenses and troubleshoot licensing problems on your test systems.")" is the **SmarTest software**.
- The "[license server](https://lhc.advantest.com/books/license-server-setup "This section covers licensing requirements and considerations you will want to examine before installing your licenses.")" is first of all a **third-party licensing software,** like the FLEXlm software, which controls the licenses. Sometimes also the hardware, where the license server runs, is referred to as "license server".

</div>The **license server** software can **either run on the system controller** together with the SmarTest software, or on a **separate server hardware.**

<p class="callout info"><span class="title">Note: If you plan to use a local license server, for example to run SmarTest in offline mode, you must install the FLEXlm license package on the System Controller and use it as local license server host. For the offline usage of SmarTest, add an offline license file to the folder **<span class="filepath">/opt/flexlm/license</span>.**</span></p>

<div id="bkmrk-supported-license-se"><section class="section">### Supported license server configurations

Advantest supports three types of license server configurations:

- Local license server
- Central license server
- Three-license-server redundancy configuration

</section><section class="section">### Local license server

In a local license server configuration the license server runs on the system controller together with the SmarTest software; i.e. both run on the same machine.

</section><section class="section">### Central license server

In a central license server configuration the SmarTest software runs on the system controller. The central license server runs on a dedicated machine.

</section><section class="section">### Three-license-server redundancy configuration

In a redundancy configuration with three license servers, each of the three license servers runs on its own dedicated machine and can serve the same set of licenses. The three-license-server redundancy configuration ensures the reliability of the license issuing: One of the three license servers acts as master and serves the licenses. If for example the master license servers fails, one of the remaining two license servers will become the new master and serves the licenses. For issuing licenses at least two of the three dedicated license servers must run.

</section></div><nav id="bkmrk-related-information-" role="navigation">### Related information

<div class="ri"><div>[Set up a three-license-server redundancy configuration](https://lhc.advantest.com/books/license-server-setup/page/license-server-setup#bkmrk-set-up-a-three-licen "In a redundancy configuration with three license servers, each of the three license servers runs on its own dedicated machine. Two servers are used to serve licenses and their license files must be kept synchronized. The third server is required to build the quorum, participating in monitoring the availability of at least one license server, but does not serve licenses. Licenses do not need to be installed on the third server.")</div><div>[Client configuration and license management](https://lhc.advantest.com/books/client-configuration-and-license-management "License configuration and license management on a license client provide you with the tools and utilities to help you to administer licenses and troubleshoot licensing problems on your test systems.")</div><div>[License server setup](https://lhc.advantest.com/books/license-server-setup "This section covers licensing requirements and considerations you will want to examine before installing your licenses.")</div></div></nav>