Sendmail has some features that are very useful that are marked as For Future Release (FFR).

One of these is a change in vacation that skips the check for To: or CC: and replies to 
every email.  Since I use a lot of aliases and so do the users I help support, skipping 
this check is sometimes quite useful.

To implement this feature, add this line to vacation/Makefile.m4 prior to making your 
vacation binary:

  APPENDDEF(`confENVDEF', `-D_FFR_RESPOND_ALL')

as such:

  dnl $Id: Makefile.m4,v 8.24.4.1 2002/06/21 21:58:50 ca Exp $
  include(confBUILDTOOLSDIR`/M4/switch.m4')
  
  define(`confREQUIRE_LIBSM', `true')
  # sendmail dir
  SMSRCDIR=       ifdef(`confSMSRCDIR', `confSMSRCDIR', `${SRCDIR}/sendmail')
  PREPENDDEF(`confENVDEF', `confMAPDEF')
  PREPENDDEF(`confINCDIRS', `-I${SMSRCDIR} ')
  
  bldPRODUCT_START(`executable', `vacation')
  define(`bldSOURCES', `vacation.c ')
  bldPUSH_SMLIB(`sm')
  bldPUSH_SMLIB(`smutil')
  bldPUSH_SMLIB(`smdb')
  APPENDDEF(`confENVDEF', `-DNOT_SENDMAIL')
  APPENDDEF(`confENVDEF', `-D_FFR_RESPOND_ALL')            <-----
  bldPRODUCT_END
  
  bldPRODUCT_START(`manpage', `vacation')
  define(`bldSOURCES', `vacation.1')
  bldPRODUCT_END
  
  bldFINISH


Then, in your .forward file, instead of a line such as:

  kmcgrail, "|/usr/adm/sm.bin/vacation -a kevin -a kmcgrail -a kam -a anotheralias kmcgrail"

You use:

  kmcgrail, "|/usr/adm/sm.bin/vacation -j kmcgrail"