diff --git a/Makefile.am b/Makefile.am
index 459931e..5b61f08 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -65,6 +65,7 @@ handwritten_tests = \
 	t/builtinfw_query.pl \
 	t/get_ip_from_if.pl \
 	t/geturl_connectivity.pl \
+	t/group_hosts_by.pl \
 	t/interval_expired.pl \
 	t/is-and-extract-ipv4.pl \
 	t/is-and-extract-ipv6.pl \
diff --git a/configure.ac b/configure.ac
index f65b8b3..d1fc02c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -49,6 +49,7 @@ AC_SUBST([PERL])
 # package doesn't depend on all of them, so their availability can't
 # be assumed.
 m4_foreach_w([_m], [
+    Data::Dumper
     File::Basename
     File::Path
     File::Temp
@@ -63,7 +64,6 @@ m4_foreach_w([_m], [
 # then some tests will fail. Only prints a warning if not installed.
 m4_foreach_w([_m], [
     B
-    Data::Dumper
     File::Spec::Functions
     File::Temp
   ], [AX_PROG_PERL_MODULES([_m], [],
diff --git a/ddclient.in b/ddclient.in
index cbd009a..2bf68e8 100755
--- a/ddclient.in
+++ b/ddclient.in
@@ -15,6 +15,7 @@ package ddclient;
 require v5.10.1;
 use strict;
 use warnings;
+use Data::Dumper;
 use File::Basename;
 use File::Path qw(make_path);
 use File::Temp;
@@ -3421,13 +3422,14 @@ sub get_ipv6 {
 ## group_hosts_by
 ######################################################################
 sub group_hosts_by {
-##TODO - Update for wantipv4 and wantipv6
     my ($hosts, $attributes) = @_;
-    my %attrs = (map({ ($_ => 1) } @$attributes), 'wantip' => 1);
+    my %attrs = map({ ($_ => 1) } @$attributes);
     my @attrs = sort(keys(%attrs));
     my %groups = ();
+    my $d = Data::Dumper->new([])->Indent(0)->Sortkeys(1)->Terse(1)->Useqq(1);
     for my $h (@$hosts) {
-        my $sig = join(',', map({ sprintf("%s=%s", $_, $config{$h}{$_} // '') } @attrs));
+        my %cfg = map({ ($_ => $config{$h}{$_}); } grep(exists($config{$h}{$_}), @attrs));
+        my $sig = $d->Reset()->Values([\%cfg])->Dump();
         push @{$groups{$sig}}, $h;
     }
     return %groups;
@@ -3980,7 +3982,7 @@ sub nic_dyndns2_update {
     debug("\nnic_dyndns2_update -------------------");
 
     ## group hosts with identical attributes together
-    my %groups = group_hosts_by([ @_ ], [ qw(login password server static custom wildcard mx backupmx) ]);
+    my %groups = group_hosts_by(\@_, [qw(login password server static custom wildcard mx backupmx wantipv4 wantipv6)]);
 
     my %errors = (
        'badauth'  => 'Bad authorization (username or password)',
@@ -4275,7 +4277,7 @@ sub nic_noip_update {
     debug("\nnic_noip_update -------------------");
 
     ## group hosts with identical attributes together
-    my %groups = group_hosts_by([ @_ ], [ qw(login password server static custom wildcard mx backupmx) ]);
+    my %groups = group_hosts_by(\@_, [qw(login password server static custom wildcard mx backupmx wantipv4 wantipv6)]);
 
     my %errors = (
         'badauth'  => 'Invalid username or password',
@@ -4622,7 +4624,7 @@ sub nic_zoneedit1_update {
     debug("\nnic_zoneedit1_update -------------------");
 
     ## group hosts with identical attributes together
-    my %groups = group_hosts_by([ @_ ], [ qw(login password server zone) ]);
+    my %groups = group_hosts_by(\@_, [qw(login password server zone wantip)]);
 
     ## update each set of hosts that had similar configurations
     for my $sig (keys %groups) {
@@ -5709,7 +5711,7 @@ sub nic_godaddy_update {
     debug("\nnic_godaddy_update --------------------");
 
     ## group hosts with identical attributes together
-    my %groups = group_hosts_by([ @_ ], [ qw(server login password zone) ]);
+    my %groups = group_hosts_by(\@_, [qw(server login password zone wantipv4 wantipv6)]);
 
     ## update each set of hosts that had similar configurations
     for my $sig (keys %groups) {
@@ -5846,7 +5848,7 @@ sub nic_googledomains_update {
     debug("\nnic_googledomains_update -------------------");
 
     ## group hosts with identical attributes together
-    my %groups = group_hosts_by([ @_ ], [ qw(server login password) ]);
+    my %groups = group_hosts_by(\@_, [qw(server login password wantip)]);
 
     ## update each set of hosts that had similar configurations
     for my $sig (keys %groups) {
@@ -6026,7 +6028,7 @@ sub nic_nsupdate_update {
     debug("\nnic_nsupdate_update -------------------");
 
     ## group hosts with identical attributes together
-    my %groups = group_hosts_by([ @_ ], [ qw(login password server zone) ]);
+    my %groups = group_hosts_by(\@_, [qw(login password server zone wantipv4 wantipv6)]);
 
     ## update each set of hosts that had similar configurations
     for my $sig (keys %groups) {
@@ -6143,7 +6145,7 @@ sub nic_cloudflare_update {
     debug("\nnic_cloudflare_update -------------------");
 
     ## group hosts with identical attributes together
-    my %groups = group_hosts_by([ @_ ], [ qw(ssh login password server wildcard mx backupmx zone) ]);
+    my %groups = group_hosts_by(\@_, [qw(ssh login password server wildcard mx backupmx zone wantipv4 wantipv6)]);
 
     ## update each set of hosts that had similar configurations
     for my $sig (keys %groups) {
@@ -6291,7 +6293,7 @@ sub nic_hetzner_update {
     debug("\nnic_hetzner_update -------------------");
 
     ## group hosts with identical attributes together
-    my %groups = group_hosts_by([ @_ ], [ qw(ssh login password server wildcard mx backupmx zone) ]);
+    my %groups = group_hosts_by(\@_, [qw(ssh login password server wildcard mx backupmx zone wantipv4 wantipv6)]);
 
     ## update each set of hosts that had similar configurations
     for my $sig (keys %groups) {
@@ -6448,7 +6450,7 @@ sub nic_yandex_update {
     debug("\nnic_yandex_update -------------------");
 
     ## group hosts with identical attributes together
-    my %groups = group_hosts_by([ @_ ], [ qw(server login pasword) ]);
+    my %groups = group_hosts_by(\@_, [qw(server login pasword wantip)]);
 
     ## update each set of hosts that had similar configurations
     for my $sig (keys %groups) {
@@ -7339,7 +7341,7 @@ EoEXAMPLE
 }
 
 sub nic_cloudns_update {
-    my %groups = group_hosts_by([ @_ ], [ qw(dynurl) ]);
+    my %groups = group_hosts_by(\@_, [qw(dynurl wantip)]);
     for my $hr (values(%groups)) {
         my @hosts = @$hr;
         my $hosts = join(',', @hosts);
diff --git a/t/group_hosts_by.pl b/t/group_hosts_by.pl
new file mode 100644
index 0000000..61acd0f
--- /dev/null
+++ b/t/group_hosts_by.pl
@@ -0,0 +1,90 @@
+use Test::More;
+SKIP: { eval { require Test::Warnings; } or skip($@, 1); }
+eval { require 'ddclient'; } or BAIL_OUT($@);
+eval { require Data::Dumper; } or skip($@, 1);
+Data::Dumper->import();
+
+my $h1 = 'h1';
+my $h2 = 'h2';
+my $h3 = 'h3';
+
+$ddclient::config{$h1} = {
+    common => 'common',
+    h1h2 => 'h1 and h2',
+    unique => 'h1',
+    falsy => 0,
+    maybeunset => 'unique',
+};
+$ddclient::config{$h2} = {
+    common => 'common',
+    h1h2 => 'h1 and h2',
+    unique => 'h2',
+    falsy => '',
+    maybeunset => undef,  # should not be grouped with unset
+};
+$ddclient::config{$h3} = {
+    common => 'common',
+    h1h2 => 'unique',
+    unique => 'h3',
+    falsy => undef,
+    # maybeunset is intentionally not set
+};
+
+my @test_cases = (
+    {
+        desc => 'empty attribute set yields single group with all hosts',
+        groupby => [qw()],
+        want => [[$h1, $h2, $h3]],
+    },
+    {
+        desc => 'common attribute yields single group with all hosts',
+        groupby => [qw(common)],
+        want => [[$h1, $h2, $h3]],
+    },
+    {
+        desc => 'subset share a value',
+        groupby => [qw(h1h2)],
+        want => [[$h1, $h2], [$h3]],
+    },
+    {
+        desc => 'all unique',
+        groupby => [qw(unique)],
+        want => [[$h1], [$h2], [$h3]],
+    },
+    {
+        desc => 'combination',
+        groupby => [qw(common h1h2)],
+        want => [[$h1, $h2], [$h3]],
+    },
+    {
+        desc => 'falsy values',
+        groupby => [qw(falsy)],
+        want => [[$h1], [$h2], [$h3]],
+    },
+    {
+        desc => 'set, unset, undef',
+        groupby => [qw(maybeunset)],
+        want => [[$h1], [$h2], [$h3]],
+    },
+    {
+        desc => 'missing attribute',
+        groupby => [qw(thisdoesnotexist)],
+        want => [[$h1, $h2, $h3]],
+    },
+);
+
+for my $tc (@test_cases) {
+    my %got = ddclient::group_hosts_by([$h1, $h2, $h3], $tc->{groupby});
+    # %got is used as a set of sets.  Sort everything to make comparison easier.
+    my @got = sort({
+        for (my $i = 0; $i < @$a && $i < @$b; ++$i) {
+            my $x = $a->[$i] cmp $b->[$i];
+            return $x if $x != 0;
+        }
+        return @$a <=> @$b;
+    } map({ [sort(@$_)]; } values(%got)));
+    is_deeply(\@got, $tc->{want}, $tc->{desc})
+        or diag(Data::Dumper->Dump([\@got, $tc->{want}], [qw(got want)]));
+}
+
+done_testing();