diff --git a/lib/App/Netdisco/DB/ResultSet/Device.pm b/lib/App/Netdisco/DB/ResultSet/Device.pm
index dda4e04a..c53043b8 100644
--- a/lib/App/Netdisco/DB/ResultSet/Device.pm
+++ b/lib/App/Netdisco/DB/ResultSet/Device.pm
@@ -399,6 +399,8 @@ sub carrying_vlan {
     die "vlan number required for carrying_vlan\n"
       if ref {} ne ref $cond or !exists $cond->{vlan};
 
+    return $rs unless $cond->{vlan};
+
     return $rs
       ->search_rs({ 'vlans.vlan' => $cond->{vlan} },
         {
@@ -449,6 +451,7 @@ sub carrying_vlan_name {
     die "vlan name required for carrying_vlan_name\n"
       if ref {} ne ref $cond or !exists $cond->{name};
 
+    $cond->{'vlans.vlan'} = { '>' => 0 };
     $cond->{'vlans.description'} = { '-ilike' => delete $cond->{name} };
 
     return $rs
diff --git a/lib/App/Netdisco/Web/Plugin/Device/Vlans.pm b/lib/App/Netdisco/Web/Plugin/Device/Vlans.pm
index b5d504a9..e5111e07 100644
--- a/lib/App/Netdisco/Web/Plugin/Device/Vlans.pm
+++ b/lib/App/Netdisco/Web/Plugin/Device/Vlans.pm
@@ -17,7 +17,8 @@ get '/ajax/content/device/vlans' => require_login sub {
 
     my $device = schema('netdisco')->resultset('Device')
       ->search_for_device($q) or send_error('Bad device', 400);
-    my @results = $device->vlans->search( {}, { order_by => 'vlan' } )->hri->all;
+    my @results = $device->vlans->search(
+      { vlan => { '>' => 0 } }, { order_by => 'vlan' } )->hri->all;
 
     return unless scalar @results;
 
diff --git a/lib/App/Netdisco/Web/Plugin/Report/VlanInventory.pm b/lib/App/Netdisco/Web/Plugin/Report/VlanInventory.pm
index 9a2945d3..866753fe 100644
--- a/lib/App/Netdisco/Web/Plugin/Report/VlanInventory.pm
+++ b/lib/App/Netdisco/Web/Plugin/Report/VlanInventory.pm
@@ -16,7 +16,10 @@ register_report(
 
 get '/ajax/content/report/vlaninventory' => require_login sub {
     my @results = schema('netdisco')->resultset('DeviceVlan')->search(
-        { 'me.description' => { '!=', 'NULL' } },
+        { 'me.description' => { '!=', 'NULL' },
+          'me.vlan' => { '>' => 0 },
+          'ports.vlan' => { '>' => 0 },
+        },
         {   join   => { 'ports' => 'vlan' },
             select => [
                 'me.vlan',
diff --git a/lib/App/Netdisco/Worker/Plugin/Discover/VLANs.pm b/lib/App/Netdisco/Worker/Plugin/Discover/VLANs.pm
index adf0cf08..2bf99039 100644
--- a/lib/App/Netdisco/Worker/Plugin/Discover/VLANs.pm
+++ b/lib/App/Netdisco/Worker/Plugin/Discover/VLANs.pm
@@ -48,6 +48,7 @@ register_worker({ phase => 'main', driver => 'snmp' }, sub {
       my $type = $i_vlan_type->{$entry};
 
       foreach my $vlan (@{ $i_vlan_membership_untagged->{$entry} || [] }) {
+          next unless $vlan;
           next if $this_port_vlans{$vlan};
           my $native = ((defined $i_vlan->{$entry})
                           and ($vlan eq $i_vlan->{$entry})) ? 't' : 'f';
@@ -66,6 +67,7 @@ register_worker({ phase => 'main', driver => 'snmp' }, sub {
       }
 
       foreach my $vlan (@{ $i_vlan_membership->{$entry} || [] }) {
+          next unless $vlan;
           next if $this_port_vlans{$vlan};
           my $native = ((defined $i_vlan->{$entry})
                           and ($vlan eq $i_vlan->{$entry})) ? 't' : 'f';
@@ -100,6 +102,7 @@ register_worker({ phase => 'main', driver => 'snmp' }, sub {
   # add named vlans to the device
   foreach my $entry (keys %$v_name) {
       my $vlan = $v_index->{$entry};
+      next unless $vlan;
       next unless defined $vlan and $vlan;
       ++$d_seen{$vlan};
 
@@ -112,6 +115,7 @@ register_worker({ phase => 'main', driver => 'snmp' }, sub {
 
   # also add unnamed vlans to the device
   foreach my $vlan (keys %p_seen) {
+      next unless $vlan;
       next if $d_seen{$vlan};
       push @devicevlans, {
           vlan => $vlan,
diff --git a/lib/App/Netdisco/Worker/Plugin/Macsuck/Nodes.pm b/lib/App/Netdisco/Worker/Plugin/Macsuck/Nodes.pm
index 9ea9dfb9..fc96e8f1 100644
--- a/lib/App/Netdisco/Worker/Plugin/Macsuck/Nodes.pm
+++ b/lib/App/Netdisco/Worker/Plugin/Macsuck/Nodes.pm
@@ -54,8 +54,9 @@ register_worker({ phase => 'main', driver => 'snmp' }, sub {
   # reverse sort allows vlan 0 entries to be included only as fallback
   foreach my $vlan (reverse sort keys %$fwtable) {
       foreach my $port (keys %{ $fwtable->{$vlan} }) {
+          my $vlabel = ($vlan ? $vlan : 'unknown');
           debug sprintf ' [%s] macsuck - port %s vlan %s : %s nodes',
-            $device->ip, $port, $vlan, scalar keys %{ $fwtable->{$vlan}->{$port} };
+            $device->ip, $port, $vlabel, scalar keys %{ $fwtable->{$vlan}->{$port} };
 
           # make sure this port is UP in netdisco (unless it's a lag master,
           # because we can still see nodes without a functioning aggregate)
@@ -200,7 +201,7 @@ sub get_vlan_list {
   }
 
   debug sprintf ' [%s] macsuck - VLANs: %s', $device->ip,
-    (join ',', sort keys %vlans);
+    (join ',', sort grep {$_} keys %vlans);
 
   my @ok_vlans = ();
   foreach my $vlan (sort keys %vlans) {
@@ -240,11 +241,12 @@ sub get_vlan_list {
           next;
       }
 
-      if ($vlan == 0 or $vlan > 4094) {
+      if ($vlan > 4094) {
           debug sprintf ' [%s] macsuck - invalid VLAN number %s',
             $device->ip, $vlan;
           next;
       }
+      next if $vlan == 0; # quietly skip
 
       # check in use by a port on this device
       if (!$vlans{$vlan} && !setting('macsuck_all_vlans')) {
diff --git a/share/views/ajax/device/ports.tt b/share/views/ajax/device/ports.tt
index ec10e2df..d373a90b 100644
--- a/share/views/ajax/device/ports.tt
+++ b/share/views/ajax/device/ports.tt
@@ -189,14 +189,16 @@
         data-field="c_pvid" data-for-device="[% device.ip | html_entity %]" data-for-port="[% row.port | html_entity %]">
       <i class="icon-edit nd_edit-icon"></i>
       <div class="nd_editable-cell-content">
-        [% IF row.vlan %][% row.vlan | html_entity %][% END %]
+        [% IF row.vlan AND row.vlan > 0 %][% row.vlan | html_entity %][% END %]
       </div>
       </td>
       [% ELSE %]
       <td>
+        [% IF row.vlan AND row.vlan > 0 %]
         <a class="nd_linkcell"
           href="[% uri_for('/search') %]?tab=vlan&q=[% row.vlan | uri %]">
             [% row.vlan | html_entity %]</a>
+        [% END %]
       </td>
       [% END %]
       [% END %]
@@ -204,14 +206,16 @@
       [% IF params.c_vmember %]
       <td>
         [% IF vlans.$portname.vlan_count <= settings.devport_vlan_limit %]
+          [% SET vlan_count = vlans.$portname.vlan_count %]
           [% SET output = '' %]
           [% FOREACH vlan IN vlans.$portname.vlan_set.nsort %]
+            [% IF vlan == 0 %][% SET vlan_count = (vlan_count - 1) %][% NEXT %][% END %]
             [% SET output = output _
               '<a href="' _ uri_for('/search') _ '?tab=vlan&q=' _ vlan _ '">' _ vlan _ '</a>' %]
             [% SET output = output _ ', ' IF NOT loop.last %]
           [% END %]
-          [% IF vlans.$portname.vlan_count > 10 %] [%# TODO make this a settable variable %]
-            [% SET output = '<div class="nd_vlan-total">(' _ vlans.$portname.vlan_count
+          [% IF vlan_count > 10 %] [%# TODO make this a settable variable %]
+            [% SET output = '<div class="nd_vlan-total">(' _ vlan_count
               _ ')</div><span class="nd_linkcell nd_collapse-vlans">
                 <div class="nd_arrow-up-down-left icon-chevron-up icon-large"></div>Show VLANs</span>
                 <div class="nd_collapsing nd_collapse-pre-hidden">' _ output %]