exim_routers:
  - storyboard_verp_router: |
      driver = dnslookup
      # we only consider messages sent in through loopback
      condition = ${if or{{eq{$sender_host_address}{127.0.0.1}}\
                          {eq{$sender_host_address}{::1}}}{yes}{no}}
      # we do not do this for traffic going to the local machine
      domains = '!+local_domains'
      ignore_target_hosts = <; \
            0.0.0.0; \
            64.94.110.11; \
            127.0.0.0/8; \
            ::1/128; \
            fe80::/10; \
            fec0::/10; \
            ff00::/8
      # only the un-VERPed bounce addresses are handled
      senders = "*-bounces@*"
      transport = storyboard_verp_smtp
  - storyboard: |
      # Send bounces to /dev/null until storyboard supports them.
      driver = redirect
      local_parts = storyboard
      local_part_suffix_optional = true
      local_part_suffix = -bounces : -bounces+*
      data = :blackhole:
exim_transports:
  - storyboard_verp_smtp: |
      driver = smtp
      return_path = \
        ${local_part:$return_path}+$local_part=$domain@${domain:$return_path}
      max_rcpt = 1
      headers_remove = Errors-To
      headers_add = Errors-To: ${return_path}