diff --git a/Changes b/Changes
index f7158a18..96406a38 100644
--- a/Changes
+++ b/Changes
@@ -15,6 +15,7 @@
   [BUG FIXES]
 
   * Specific search from titlebar uses default sidebar settings
+  * Fix Device Ports search for VLAN prefer with non-numeric value
 
 2.036011 - 2017-10-09
 
diff --git a/lib/App/Netdisco/Web/Plugin/Device/Ports.pm b/lib/App/Netdisco/Web/Plugin/Device/Ports.pm
index c791979a..0e9f66b8 100644
--- a/lib/App/Netdisco/Web/Plugin/Device/Ports.pm
+++ b/lib/App/Netdisco/Web/Plugin/Device/Ports.pm
@@ -23,7 +23,9 @@ get '/ajax/content/device/ports' => require_login sub {
     # refine by ports if requested
     my $f = param('f');
     if ($f) {
-        if (($prefer eq 'vlan') or not $prefer and $f =~ m/^\d+$/) {
+        if (($prefer eq 'vlan') or (not $prefer and $f =~ m/^\d+$/)) {
+            return unless $f =~ m/^\d+$/;
+
             if (param('invert')) {
                 $set = $set->search({
                   'me.vlan' => { '!=' => $f },