TCPIPSECURITY prevents the unauthorized use of well-known TCP/IP port numbers 1 through 1023. Sessions using well-known ports are not permitted for any program that is not properly authorized. Your security administrator can authorize programs that use well-known ports by using the MP (Mark Program) system command to mark the programs with a service attribute of TCPIP.

To mark programs with the TCPIP service attribute, enter the following:

MP <program name> + SERVICE “TCPIP”

Programs supplied by Unisys are appropriately marked. A warning message is generated by TCP/IP for any program requesting a well-known port number that is not marked.

Opening subports using well-known port numbers is not permitted for any program that is not authorized. User-written applications that provide well-known port numbers can be authorized by marking the code file with SERVICE=TCPIP by a security administrator.

See TCP/IP Port Numbers for more information on well-known ports.