[exim] Centos Application Applience Routing mail to relay

Hi. I’m building an appliance on the Centos distribution and have a need to run a simple mail server which stores and forwards mail to a smarthost which delivers the mail for me.

I have installed and configured Exim to accept mail on the appliances loopback address 127.0.0.1 and this works OK accept it is taking several seconds to submit a mail to Exim.

When I run a debug it looks like Exim is trying to perform a DNS lookup of 127.0.0.1

I can see how this is important for preventing spamming but would prefer not to have to install bind just to resolve a local host address. Installing bind does resolve the lookup issue by the way.

I can see that I can disable a number of lookup features in exim.conf but all that happens is the problem is pushed further down the chain until I get to the following lookup which does not have any config to adjust in exim.conf

helo

3425 Connection request from 127.0.0.1 port 53118
3425 search_tidyup called
3427 host in rfc1413_hosts? no (end of list)
3427 sender_fullhost = [127.0.0.1]
3427 sender_rcvhost = [127.0.0.1]
3427 Process 3427 is handling incoming connection from [127.0.0.1]
3427 host in host_lookup? no (end of list)
3427 set_process_info: 3427 handling incoming connection from [127.0.0.1]
3427 host in host_reject_connection? no (option unset)
3427 host in sender_unqualified_hosts? no (option unset)
3427 host in recipient_unqualified_hosts? no (option unset)
3427 host in helo_verify_hosts? no (option unset)
3427 host in helo_try_verify_hosts? no (option unset)
3427 host in helo_accept_junk_hosts? no (option unset)
3427 SMTP>> 220 host01 ESMTP Exim 4.63 Sat, 13 Oct 2012 10:33:46 +0100
3427 Process 3427 is ready for new message
3427 smtp_setup_msg entered
3425 1 SMTP accept process running
3425 Listening...
3427 SMTP<< EHLO host01
3427 uvos01 in helo_lookup_domains? yes (matched "@")
3427 looking up host name for 127.0.0.1

Eventually the lookup times out and the mail is sent. What's correct way to resolve the issue? Is there further lookups to disable or can exim resolve 127.0.0.1 via another method other than a DNS server?



Below is the route I am testing

Many thanks

smarthost:
driver = manualroute
domains = ! +local_domains
transport = remote_smtp
route_data = 172.16.1.100
no_more

remote_smtp:
driver = smtp