system.filter

#
# This is an example Exim system filter to be used in conjuncation with the ocmailinglists script
#

# modify mails going to mailing list domains
if first_delivery and $recipients contains "@domain.com" 
then

  # add list name to subject, if only the list is in the to header (avoids adding this to replies)
  headers add "Old-Subject: $h_subject"
  if ${local_part:$recipients} is not ""
  then
    headers remove "Subject"
    headers add "Subject: [${local_part:$recipients}] $h_old-subject"
    headers remove "Old-Subject"
  endif

  # remove DKIM as we modify the header from
  headers remove "DKIM-Signature"

  # set reply to header, only if it was not set before
  headers add "X-Reply-Address: $reply_address"
  headers remove "Reply-To"
  headers add "Reply-To: $h_x-reply-address"
  headers remove "X-Reply-Address"

  # set from header to a the local domains
  headers add "X-Original-From: $h_from"
  headers remove "From"
  headers add "From: \"${sg{$header_x-original-from:}{\"}{}}\" <noreply@domain.com>"

  # mark this mail as list mail
  headers add "Precedence: list"
endif