# callout with no transport
need_ipv4
#
server PORT_S
220 Welcome
HELO
250 Hi
MAIL FROM
250 OK
RCPT TO
550 unrouteable address
QUIT
221 Bye
****
exim -bs
mail from:<unknown@x.x.x.x>
rcpt to:<unknown@u.u.u.u>
quit
****