Why not to change exim's default configuration file like this,
i.e. to use it for local delivery only BY DEFAULT?

--- /usr/pkg/share/examples/exim/configure      2006-03-15 23:59:58.000000000 +0000
+++ /usr/pkg/etc/exim/configure 2006-03-19 18:39:03.000000000 +0000
@@ -43,6 +43,9 @@
 #                    MAIN CONFIGURATION SETTINGS                     #
 ######################################################################
 
+# Listen to loopback only
+local_interfaces = 127.0.0.1 : ::::1
+
 # Specify your host's canonical name here. This should normally be the fully
 # qualified "official" name of your host. If this option is not set, the
 # uname() function is called to obtain the name. In many cases this does
@@ -56,7 +59,7 @@
 # +local_domains, +relay_to_domains, and +relay_from_hosts, respectively. They
 # are all colon-separated lists:
 
-domainlist local_domains = @
+domainlist local_domains = @ : localhost
 domainlist relay_to_domains =
 hostlist   relay_from_hosts = 127.0.0.1
 


-- 
Best regards, Aleksey Cheusov.