Library /sys$common/syshlp/tcpip$nslookup_help.hlb set, search  *Conan The Librarian (sorry for the slow response - running on an old VAX)

   If a lookup request contains at least one period but doesn't
   end with a trailing period, append the domain manes in the
   domain search list until an answer is received.

   FORMAT:
    set [no]search

   DEFAULT:
    set search