--- a/exim4.conf	Fri Dec 20 23:15:02 2013 +0100
+++ b/exim4.conf	Fri Dec 20 23:39:18 2013 +0100
@@ -6,19 +6,24 @@
 # in one place. This place is the "providers" file. The structure
 # is simple. It consists of lines as in the example:
 #
-# # sender     |server[:port]  |user|password
-# # -----------+---------------+----+---------
-# foo@bar.com	foobar.com      foo  secret
-# *@bar.com     bar.com/mx:smtp fuz  secret2
-# *		smtp.gmail.com  xxx  baz
+# # sender     |servers[::port]  |user|password
+# # -----------+-----------------+----+---------
+# foo@bar.com	foobar.com       foo  secret
+# baz@bar.com   a.com:b.com::25  foo  sicrit
+# *@bar.com     bar.com/mx:25    fuz  secret2
+# *		smtp.gmail.com   xxx  baz
+#
+# Note: the "servers::[port]" field is used as "route_data", thus all
+# rules for route_data apply (see spec.txt, 20.3). 
+# - multiple servers are colon (:) separated
+# - you can use indirect lists by appending /mx
+# - you can specifiy a port number numerically (per default we use 587)
 
 PROVIDERS = <your file name for the providers file here>
 
 # some macros to ease the understanding
 ADDRESS_DATA = ${sg{${lookup{$sender_address}lsearch*@{PROVIDERS}}}{\\s+}{\t}}
 SMARTHOST    = ${extract{1}{\t}{$address_data}}
-HOST         = ${extract{1}{:}{SMARTHOST}}
-PORT         = ${extract{2}{:}{SMARTHOST}{$value}{submission}}
 USER         = ${extract{2}{\t}{$address_data}}
 PASS         = ${extract{3}{\t}{$address_data}}
 
@@ -30,7 +35,7 @@
 smarthost:
 	driver = manualroute
 	address_data = ADDRESS_DATA
-	route_data = HOST
+	route_data = SMARTHOST
 	transport = smtp_auth
 
 # in case you don't have a '*' line in your providers file
@@ -45,8 +50,8 @@
 
 smtp_auth:
 	driver = smtp
+	port = submission
 	hosts_require_auth = *
-	port = PORT
 
 smtp:
 	driver = smtp
@@ -58,7 +63,6 @@
 	public_name = PLAIN
 	client_send = ^USER^PASS
 	
-
 login:
 	driver = plaintext
 	public_name = LOGIN