Allows a program or an operator to designate the remote LUs from which the local LU will accept consecutive allocation requests that, once verified, remain verified for specific user IDs.

Support for this option set is provided by APPC/MVS, ACF/VTAM (release 3.4 or later), and RACF (release 1.9.2 or later). VTAM support for this option set is provided by keyword values of the SECACPT operand on the VTAM APPL statement. RACF support for this option set is provided by keyword values of the CONVSEC field in the SESSION segment of the RACF APPCLU profile. APPC/MVS support for this option set is provided in its TP attach processing, which uses RACF services to inspect and maintain the LU's SIGNED_ON_FROM list.