if !/^Received: +from +[^[]+\[10\.44\.241\.[0-9]+\]/
/^Received: +from +((\w+\.)*oern\.mine\.nu|10\.44\.241\.[0-9]+) +/
  reject forged client name in Received: header: $1
endif

if !/^Received: +from +[^[]+\[10\.44\.241\.[0-9]+\]/
/^Received: +from +[^ ]+ +\(([^ ]+ +[he]+lo=|[he]+lo +)((\w+\.)*oern\.mine\.nu|10\.44\.241\.[0-9]+)\)/
  reject forged client name in Received: header: $2
endif