diff --git a/src/etc/inc/plugins.inc.d/kea.inc b/src/etc/inc/plugins.inc.d/kea.inc
index 67efae8aa2b..f3cb5cade91 100644
--- a/src/etc/inc/plugins.inc.d/kea.inc
+++ b/src/etc/inc/plugins.inc.d/kea.inc
@@ -118,6 +118,18 @@ function kea_staticmap($proto = null, $valid_addresses = true, $ifconfig_details
                 }
             }
 
+            // Use the first search list domain for DNS registration
+            if ($proto == 6) {
+                $subnet_node = $keamdl->getNodeByReference("subnets.subnet6.{$reservation->subnet}");
+                if ($subnet_node) {
+                    if (!empty((string)$reservation->domain_search)) {
+                        $domain = explode(',', (string)$reservation->domain_search)[0];
+                    } elseif (!empty((string)$subnet_node->option_data->domain_search)) {
+                        $domain = explode(',', (string)$subnet_node->option_data->domain_search)[0];
+                    }
+                }
+            }
+
             $entry = [
                 'descr' => $description,
                 'domain' => $domain,
diff --git a/src/opnsense/mvc/app/controllers/OPNsense/Kea/forms/dialogReservation6.xml b/src/opnsense/mvc/app/controllers/OPNsense/Kea/forms/dialogReservation6.xml
index b850f4b81d6..edb00cb7cb7 100644
--- a/src/opnsense/mvc/app/controllers/OPNsense/Kea/forms/dialogReservation6.xml
+++ b/src/opnsense/mvc/app/controllers/OPNsense/Kea/forms/dialogReservation6.xml
@@ -30,7 +30,7 @@
         <style>tokenize</style>
         <allownew>true</allownew>
         <separator>,</separator>
-        <help>Specifies a ´search list´ of Domain Names to be used by the client to locate not-fully-qualified domain names.</help>
+        <help>Specifies a ´search list´ of Domain Names to be used by the client to locate not-fully-qualified domain names. The first domain in this list will also be used for DNS registration of this host if enabled. If empty, the first domain in the interface's domain search list will be used. If this is empty, too, the system domain will be used.</help>
         <grid_view>
             <visible>false</visible>
         </grid_view>
diff --git a/src/opnsense/mvc/app/controllers/OPNsense/Kea/forms/dialogSubnet6.xml b/src/opnsense/mvc/app/controllers/OPNsense/Kea/forms/dialogSubnet6.xml
index 7304e746454..81ba746f7d4 100644
--- a/src/opnsense/mvc/app/controllers/OPNsense/Kea/forms/dialogSubnet6.xml
+++ b/src/opnsense/mvc/app/controllers/OPNsense/Kea/forms/dialogSubnet6.xml
@@ -59,7 +59,7 @@
         <style>tokenize</style>
         <allownew>true</allownew>
         <separator>,</separator>
-        <help>Specifies a ´search list´ of Domain Names to be used by the client to locate not-fully-qualified domain names.</help>
+        <help>Specifies a ´search list´ of Domain Names to be used by the client to locate not-fully-qualified domain names. The first domain in this list will also be used for DNS registration of DHCP static mappings (if enabled).</help>
         <grid_view>
             <visible>false</visible>
         </grid_view>