remote_smtp_dkim:
  debug_print = "T: remote_smtp_dkim for $local_part@$domain"
  driver = smtp
.ifdef REMOTE_SMTP_HOSTS_AVOID_TLS
  hosts_avoid_tls = REMOTE_SMTP_HOSTS_AVOID_TLS
.endif
.ifdef REMOTE_SMTP_HEADERS_REWRITE
  headers_rewrite = REMOTE_SMTP_HEADERS_REWRITE
.endif
.ifdef REMOTE_SMTP_RETURN_PATH
  return_path = REMOTE_SMTP_RETURN_PATH
.endif
.ifdef REMOTE_SMTP_HELO_DATA
  helo_data=REMOTE_SMTP_HELO_DATA
.endif
dkim_domain = ${lookup{$sender_address}lsearch*@{/etc/exim4/dkim_senders}}
dkim_selector = yourhostname
dkim_private_key = /etc/ssl/private/dkim.key
dkim_canon = relaxed
dkim_strict = false
#dkim_sign_headers = DKIM_SIGN_HEADERS