[Exim] fall through routers not working for me...

A little background...
This is for sending mail from my laptop which finds itself on many
different networks in the course of a week.
Many sites are now blocking mail that appears to come from dynamic IP
addresses ranges that they know about. Even worse - some sites are just
blocking port 25.

According to the docs (i'm using debian's 3.36-6)
Including multiple routers should cause exim to try each one in turn
until delivery is successful.

So i put in the routers section

lookuphost:
driver = lookuphost
transport = remote_smtp

literal:
driver = ipliteral
transport = remote_smtp

smarthost:
driver = domainlist
transport = remote_smtp
route_list = "* smarthost4 bydns_a"

smarthost:
driver = domainlist
transport = remote_smtp
route_list = "* smarthost2 bydns_a"

smarthost:
driver = domainlist
transport = remote_smtp
route_list = "* smarthost3 bydns_a"

thinking that if it can't deliver directly then exim will keep trying
smarthosts that it knows about it succeeds or drops off the bottom of
the list.

But sometimes mail just bounces instead of being rejected and this
scheme fails...
How can i make this work?
(i really don't want to have to set up my own smtp auth system...)


thanks for any ideas!

brad