Library /sys$common/syshlp/ncphelp.hlb SET, EXECUTOR, IDP string  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Specify this parameter if you want to use the DNS INTERFACE.
 Specifies the  IDP of the network's network service access
 point (NSAP) (global network address).  This is a string of 1
 to 22 hexadecimal digits.  The default is 49.