diff --git a/CHANGES b/CHANGES
index 949f62e..a4262b4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -7,6 +7,10 @@
 --- 2.010 2012-06-17
     * Fixed incorrect use of != instead of ne for string comparison
       (LP: #1014243)
+    ! Changed non-standard X-Comment header fields for localhost and
+      whitelisted addresses to use RFC 5451 Authentication Results header
+      fields
+    ! Added depenency on Sys::Hostname::Long for local hostname determination
 
 --- 2.009 2012-02-03
   * Chomp erroneus NULLs off the end of local and authority explanations to
diff --git a/INSTALL b/INSTALL
index edc3cec..3e13787 100644
--- a/INSTALL
+++ b/INSTALL
@@ -7,7 +7,8 @@ postfix-policyd-spf-perl:
   Perl 5.6
   version
   NetAddr-IP 4
-  Mail-SPF (not Mail-SPF-Query) version 2.006 or later
+  Mail::SPF (not Mail-SPF-Query) version 2.006 or later
+  Sys::Hostname::Long
 
 Installing
 ----------
diff --git a/postfix-policyd-spf-perl b/postfix-policyd-spf-perl
index cd31cf4..06c9a51 100755
--- a/postfix-policyd-spf-perl
+++ b/postfix-policyd-spf-perl
@@ -31,6 +31,7 @@ use IO::Handle;
 use Sys::Syslog qw(:DEFAULT setlogsock);
 use NetAddr::IP;
 use Mail::SPF;
+use Sys::Hostname::Long 'hostname_long';
 
 # ----------------------------------------------------------
 #                      configuration
@@ -92,6 +93,10 @@ use constant relay_addresses => map(
     qw(  )
 ); # add addresses to qw (  ) above separated by spaces using CIDR notation.
 
+# Fully qualified hostname, if available, for use in authentication results
+# headers now provided by the localhost and whitelist checks.
+my  $host = hostname_long;
+
 my %results_cache;  # by message instance
 
 # ----------------------------------------------------------
@@ -187,7 +192,7 @@ sub exempt_localhost {
     my $attr = $options{attr};
     if ($attr->{client_address} ne '') {
         my $client_address = NetAddr::IP->new($attr->{client_address});
-        return 'PREPEND X-Comment: SPF not applicable to localhost connection - skipped check'
+        return "PREPEND Authentication-Results: $host; none (SPF not checked for localhost)"
             if grep($_->contains($client_address), localhost_addresses);
     };
     return 'DUNNO';
@@ -202,7 +207,7 @@ sub exempt_relay {
     my $attr = $options{attr};
     if ($attr->{client_address} ne '') {
         my $client_address = NetAddr::IP->new($attr->{client_address});
-        return 'PREPEND X-Comment: SPF skipped for whitelisted relay'
+        return "PREPEND Authentication-Results: $host; none (SPF not checked for whitelisted relay)"
             if grep($_->contains($client_address), relay_addresses);
     };
     return 'DUNNO';