[exim] manualroute defer

Hi,


I've got a set of hosts that only have internal IPs that I want to be
able to deliver mail to the Internet.

I thought I could do that with a manualroute at the end of the routers
on the internal-ip-only machines, to the mailservers in the group that
do have outgoing IPs, like this:

dnslookup:
   driver               = manualroute
   transport            = internal_smtp
   route_list           = * 192.168.84.30:192.168.84.31:192.168.84.32
   no_more

but today I discovered that if the .84.30 host has nothing listening on
port 25 delivery gets deferred instead of trying .84.31 and all mail
queues up.



2019-03-27 06:48:48 1h8yLV-0005Pe-PV H=192.168.84.30 [192.168.84.30]
Connection refused

2019-03-27 06:48:48 1h8yLV-0005Pe-PV == acme@??? <acme@???>
R=dnslookup T=internal_smtp defer (111): Connection refused


I think I can work around this by using hosts_randomize, but that seems
ugly and it seems I am missing something.

Can someone shed some light on this? Should I be using multiple routers
with an option I failed to find when reading the docs?

thanks,
Maarten.

PS. Exim version 4.86_2, running on Ubuntu 16.04 with my own config.