diff --git a/lib/Mail/DMARC.pm b/lib/Mail/DMARC.pm
index 8cd57c77..9a3a3bb2 100644
--- a/lib/Mail/DMARC.pm
+++ b/lib/Mail/DMARC.pm
@@ -45,19 +45,19 @@ sub source_ip {
 
 sub envelope_to {
     return $_[0]->{envelope_to} if 1 == scalar @_;
-    croak "invalid envelope_to" if !$_[0]->is_valid_domain( $_[1] );
+    croak "invalid envelope_to" if !$_[0]->is_valid_domain( lc $_[1] );
     return $_[0]->{envelope_to} = $_[1];
 }
 
 sub envelope_from {
     return $_[0]->{envelope_from} if 1 == scalar @_;
-    croak "invalid envelope_from" if !$_[0]->is_valid_domain( $_[1] );
+    croak "invalid envelope_from" if !$_[0]->is_valid_domain( lc $_[1] );
     return $_[0]->{envelope_from} = $_[1];
 }
 
 sub header_from {
     return $_[0]->{header_from} if 1 == scalar @_;
-    croak "invalid header_from" if !$_[0]->is_valid_domain( $_[1] );
+    croak "invalid header_from" if !$_[0]->is_valid_domain( lc $_[1] );
     return $_[0]->{header_from} = lc $_[1];
 }
 
diff --git a/lib/Mail/DMARC/Base.pm b/lib/Mail/DMARC/Base.pm
index e4cf82d6..c25457a6 100644
--- a/lib/Mail/DMARC/Base.pm
+++ b/lib/Mail/DMARC/Base.pm
@@ -281,7 +281,7 @@ sub is_valid_ip {
 sub is_valid_domain {
     my ( $self, $domain ) = @_;
     return 0 if $domain !~ /^$RE{net}{domain}{-rfc1101}{-nospace}$/x;
-    my $tld = ( split /\./, lc $domain )[-1];
+    my $tld = ( split /\./, $domain )[-1];
     return 1 if $self->is_public_suffix($tld);
     $tld = join( '.', ( split /\./, $domain )[ -2, -1 ] );
     return 1 if $self->is_public_suffix($tld);
diff --git a/t/00.Dmarc.t b/t/00.Dmarc.t
index d8e6b309..543af984 100644
--- a/t/00.Dmarc.t
+++ b/t/00.Dmarc.t
@@ -225,7 +225,7 @@ sub test_spf {
 
 sub test_header_from {
 
-    my @good_vals = (qw/ spam-example.com bar.com /);
+    my @good_vals = (qw/ spam-example.com bar.com test.co.UK test.CO.za /);
     foreach my $k (@good_vals) {
         ok( $dmarc->header_from($k), "header_from, $k" );
     }