Incoming X.400 network connections from remote X.400 MTAs must be associated with the PMDF-X400 responder. On Solaris to start up the listening for incoming RFC 1006 connections over TCP/IP, you simply start up the PMDF-X400 TSAPD process. The PMDF-X400 TSAPD process listens for incoming X.400 network connections and hands them to PMDF-X400; see Section 41.7.1 for a discussion of starting up this process.