Use Microsoft IIS 7.x Web server to host relay server on any supported Windows OS host computers. IIS 7.x is the required version of IIS, if you intend to also implement load balancing with Web Platform Installer.
Tuning IIS for Improved Relay Server Performance
If relay server is installed to an IIS server, Sybase recommends tuning IIS to improve relay server performance. One best practice is to increase the number of connection pools used beyond just a single pool.