High Quality Content by WIKIPEDIA articles! Microsoft Host Integration Server (a.k.a. HIS) is a gateway application providing connectivity between Microsoft Windows networks and IBM mainframe and AS/400 systems. Support is provided for SNA, 3270 (standard and Telnet 3270 TN3270E), 5250 (standard and Telnet 5250), CICS, APPC, and other IBM protocols. Support is also provided for advanced integration with Windows networks and software, such as linking Microsoft Message Queuing applications to IBM WebSphere MQ, binding Microsoft DTC transactions with CICS, and cross-protocol access to DB2 databases on IBM platforms.