diff --git a/src/opnsense/mvc/app/library/OPNsense/Firewall/Rule.php b/src/opnsense/mvc/app/library/OPNsense/Firewall/Rule.php
index 4929c541d..473e71ac6 100644
--- a/src/opnsense/mvc/app/library/OPNsense/Firewall/Rule.php
+++ b/src/opnsense/mvc/app/library/OPNsense/Firewall/Rule.php
@@ -263,6 +263,10 @@ abstract class Rule
                         $rule[$target."_port"] = $port;
                     } elseif (Util::isAlias($port)) {
                         $rule[$target."_port"] = '$'.$port;
+                        if (!Util::isAlias($port, true)) {
+                            // unable to map port
+                            $rule['disabled'] = true;
+                        }
                     }
                 }
                 if (!isset($rule[$target])) {
diff --git a/src/opnsense/mvc/app/library/OPNsense/Firewall/SNatRule.php b/src/opnsense/mvc/app/library/OPNsense/Firewall/SNatRule.php
index e0cccc7a2..3b5a55e7a 100644
--- a/src/opnsense/mvc/app/library/OPNsense/Firewall/SNatRule.php
+++ b/src/opnsense/mvc/app/library/OPNsense/Firewall/SNatRule.php
@@ -98,6 +98,10 @@ class SNatRule extends Rule
             foreach (array("sourceport", "dstport", "natport") as $fieldname) {
                 if (!empty($rule[$fieldname]) && Util::isAlias($rule[$fieldname])) {
                     $rule[$fieldname] = "$".$rule[$fieldname];
+                    if (!Util::isAlias($rule[$fieldname], true)) {
+                        // unable to map port
+                        $rule['disabled'] = true;
+                    }
                 }
             }
             if (!empty($rule['staticnatport']) || !empty($rule['nonat'])) {