Use Microsoft Exchange Load Generator 2013 (LoadGen) as a simulation tool to measure the impact of MAPI, OWA, ActiveSync, IMAP, POP and SMTP clients on Exchange 2013 servers. LoadGen allows you to test how a server running Exchange 2013 responds to e-mail loads. To simulate the delivery of these messaging requests, you run LoadGen tests on client computers. These tests send multiple messaging requests to the Exchange server, thereby causing a mail load. LoadGen is a useful tool for administrators who are sizing servers and validating a deployment plan. Specifically, LoadGen helps you determine if each of your servers can handle the load to which they are intended to carry. Another use for LoadGen is to help validate the overall solution.
This version is intended for Microsoft Exchange 2013 Servers only.
Important! LoadGen should be used only in laboratories that have no connection to the production environment. This tool should not be used in any way in a production environment or an environment that is mission critical or contains important information of any kind anywhere in the network.
The tool is provided as-is. At this time, there are no updates or patches planned for future release. No formal support is provided for the tool. Some minimal support may be provided by Microsoft but not all reported issues will be able to be addressed or resolved.
You can also try the Exchange Server Forums on TechNet for help.