+ options) on the release of Exim 3.00. With the release of Exim
+ 4.00 the whole basis of policy checks on incoming mail changed
+ to be based on a set of Access Control Lists (ACLs) applied at
+ various during the incoming mail transaction. For this reason
+ the configuration of Exim 4.x and later to use DNSBLs is
+ complete different to that used for earlier versions.</p>
+
+ <h2>Exim 4.x DNSBL Usage</h2>
+
+ <p>In Exim 4.x a DNSBL lookup can be used in any of the incoming SMTP
+ ACLs. However it is typical for the lookups to be used in the ACL
+ handling <tt>RCPT TO</tt> - this allows policies to accept mail
+ for <tt>postmaster</tt> or other special local parts (for
+ example so a blocked sender can talk to the local postmaster
+ about getting blocks lifted or excluded)</p>
+
+ <p>The use of DNSBLs is substantially documented in the main exim
+ specification or the 4.x versions, so will not be covered in
+ detail here. However a couple of examples can be given</p>
+ <pre>
+ # Add a warning header if the sending host is in these
+ # DNSBLs but acccept the message (or rather leave it for
+ # later ACLs to accept/deny
+ warn message = X-blacklisted-at: $dnslist_domain
+ dnslists = blackholes.mail-abuse.org : \
+ dialup.mail-abuse.org
+
+
+
+ # Reject messages from senders listed in these DNSBLs
+ deny dnslists = blackholes.mail-abuse.org
+ </pre>
+
+ <p>Documentation on these features can be found in the
+ specification section on
+ <a href="../exim-html-4.20/doc/html/spec_37.html">
+ Access Control Lists</a>.</p>
+
+ <h2>Exim 3.x DNSBL Usage</h2>