diff --git a/advanced/Scripts/webpage.sh b/advanced/Scripts/webpage.sh
index 1f7cc728..ec1a763c 100755
--- a/advanced/Scripts/webpage.sh
+++ b/advanced/Scripts/webpage.sh
@@ -224,17 +224,20 @@ trust-anchor=.,20326,8,2,E06D44B80B8F1D39A95C0B0D7C65D08458E880409BBC68345710423
         REV_SERVER_TARGET="${CONDITIONAL_FORWARDING_IP}"
         add_setting "REV_SERVER_TARGET" "${REV_SERVER_TARGET}"
 
+        REV_SERVER_CIDR="${CONDITIONAL_FORWARDING_REVERSE}"
+        if [ -z "${REV_SERVER_CIDR}" ]; then
+            # Convert existing input to /24 subnet (preserves legacy behavior)
+            # This sed converts "192.168.1.2" to "192.168.1.0/24"
+            # shellcheck disable=2001
+            REV_SERVER_CIDR="$(sed "s+\\.[0-9]*$+\\.0/24+" <<< "${REV_SERVER_TARGET}")"
+        fi
+        add_setting "REV_SERVER_CIDR" "${REV_SERVER_CIDR}"
+
         # Remove obsolete settings from setupVars.conf
         delete_setting "CONDITIONAL_FORWARDING"
         delete_setting "CONDITIONAL_FORWARDING_REVERSE"
         delete_setting "CONDITIONAL_FORWARDING_DOMAIN"
         delete_setting "CONDITIONAL_FORWARDING_IP"
-
-        # Convert existing input to /24 subnet (preserves legacy behavior)
-        # This sed converts "192.168.1.2" to "192.168.1.0/24"
-        # shellcheck disable=2001
-        REV_SERVER_CIDR="$(sed "s+\\.[0-9]*$+\\.0/24+" <<< "${REV_SERVER_TARGET}")"
-        add_setting "REV_SERVER_CIDR" "${REV_SERVER_CIDR}"
     fi
 
     if [[ "${REV_SERVER}" == true ]]; then