Peers have always  used long headers internally, so this  is hardly a new
problem. The  default sendmail hop limit  of 16 is just  plain and simple
broken.  It breaks  even some  sendmail-based redistribution  lists. With
people reading  their mail  on a  PC-based mail  system sitting  behind a
firewall it doesn't take all that long to accumulate 16 hops.
 
  Eric