diff --git a/specification/network/resource-manager/Microsoft.Network/stable/2019-06-01/azureFirewall.json b/specification/network/resource-manager/Microsoft.Network/stable/2019-06-01/azureFirewall.json
index 8d8df966288c..d6e073111603 100644
--- a/specification/network/resource-manager/Microsoft.Network/stable/2019-06-01/azureFirewall.json
+++ b/specification/network/resource-manager/Microsoft.Network/stable/2019-06-01/azureFirewall.json
@@ -873,7 +873,8 @@
       "description": "The protocol type of a Application Rule resource.",
       "enum": [
         "Http",
-        "Https"
+        "Https",
+        "Mssql"
       ],
       "x-ms-enum": {
         "name": "AzureFirewallApplicationRuleProtocolType",