On OpenVMS, the Service Dispatcher requires as the underlying TCP/IP package, any one of MultiNet V3.5A or later with all UCXDRIVER patches (upgrading to MultiNet V4.0B, which requires no known patches as of this printing, is recommended), Pathway V2.5.x with all patches (in particular C82195) or later, TCPware V5.0 or later, or TCP/IP Services for OpenVMS V4.0 or later (with UCX V4.1 requiring upgrading to at least ECO 5).

On OpenVMS, note that the Service Dispatcher requires that your TCP/IP package provide UCX emulation; if your TCP/IP package is not currently configured for UCX emulation, you must enable UCX emulation.

Your TCP/IP package must be configured to include a loopback adaptor; that is, your TCP/IP package must recognize the IP address 127.0.0.1 as itself.