From 90f0ce3c7c48aafe82406e9599620c5338f11a45 Mon Sep 17 00:00:00 2001
From: Alexander Kolenaty <akolenaty@protonmail.ch>
Date: Tue, 12 May 2026 16:31:49 +0200
Subject: [PATCH] interfaces: do not drop VIP alias on description-only
 set_item

---
 .../Interfaces/Api/VipSettingsController.php  | 21 +++++++++++++------
 .../scripts/interfaces/reconfigure_vips.php   |  2 ++
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/src/opnsense/mvc/app/controllers/OPNsense/Interfaces/Api/VipSettingsController.php b/src/opnsense/mvc/app/controllers/OPNsense/Interfaces/Api/VipSettingsController.php
index d08f4dc0e3..22b2fe789f 100644
--- a/src/opnsense/mvc/app/controllers/OPNsense/Interfaces/Api/VipSettingsController.php
+++ b/src/opnsense/mvc/app/controllers/OPNsense/Interfaces/Api/VipSettingsController.php
@@ -120,14 +120,23 @@ class VipSettingsController extends ApiMutableModelControllerBase
         Config::getInstance()->lock();
         $node = $this->getModel()->getNodeByReference('vip.' . $uuid);
         $validations = [];
-        $post_subnet = '';
-        $post_interface = '';
+        $post_subnet = null;
+        $post_interface = null;
         if (isset($_POST['vip'])) {
-            $post_subnet = !empty($_POST['vip']['network']) ? explode('/', $_POST['vip']['network'])[0] : '';
-            $post_interface = !empty($_POST['vip']['interface']) ? $_POST['vip']['interface'] : '';
+            if (!empty($_POST['vip']['network'])) {
+                $post_subnet = explode('/', $_POST['vip']['network'])[0];
+            } elseif (isset($_POST['vip']['subnet'])) {
+                $post_subnet = $_POST['vip']['subnet'];
+            }
+            if (isset($_POST['vip']['interface'])) {
+                $post_interface = $_POST['vip']['interface'];
+            }
         }
 
-        if ($node != null && $post_subnet != (string)$node->subnet) {
+        $subnet_changed = $post_subnet !== null && $post_subnet != (string)$node?->subnet;
+        $interface_changed = $post_interface !== null && $post_interface != (string)$node?->interface;
+
+        if ($node != null && $subnet_changed) {
             $validations = $this->getModel()->whereUsed((string)$node->subnet);
             if (!empty($validations)) {
                 // XXX a bit unpractical, but we can not validate previous values from the model so
@@ -140,7 +149,7 @@ class VipSettingsController extends ApiMutableModelControllerBase
                 ];
             }
         }
-        if ($node != null && ($post_subnet != (string)$node->subnet || $post_interface != (string)$node->interface)) {
+        if ($node != null && ($subnet_changed || $interface_changed)) {
             $addr = (string)$node->subnet;
             if (Util::isLinkLocal($addr)) {
                 $addr .= "@{$node->interface}";
diff --git a/src/opnsense/scripts/interfaces/reconfigure_vips.php b/src/opnsense/scripts/interfaces/reconfigure_vips.php
index 8c52b70d7e..9e4f271009 100755
--- a/src/opnsense/scripts/interfaces/reconfigure_vips.php
+++ b/src/opnsense/scripts/interfaces/reconfigure_vips.php
@@ -78,6 +78,8 @@ foreach (glob("/tmp/delete_vip_*.todo") as $filename) {
         }
         if (isset($addresses[$address])) {
             legacy_interface_deladdress($addresses[$address]['if'], $address, is_ipaddrv6($address) ? 6 : 4);
+            // keep snapshot in sync so the re-add loop below sees the address as missing
+            unset($addresses[$address]);
         } else {
             // not found, likely proxy arp
             $proxyarp = true;