Answer: UCSPI-TCP is the sort of domain for the public that helps in building the client-server application of TCP using the command line tool of UNIX TCP in qmail
Step-by-step explanation: UCSPI-TCP is referred as the UNIX Client-Server Program Interface with the help of TCP (transfer control protocol) .It is usually used for the management of the IP (internet protocol) present on the server and checks which IP's should be permitted for the connection with SMTP(simple mail transfer protocol)services.It also manages the variable or the environment constant that IP want to utilize .