diff --git a/specification/network/resource-manager/Microsoft.Network/stable/2019-02-01/networkSecurityGroup.json b/specification/network/resource-manager/Microsoft.Network/stable/2019-02-01/networkSecurityGroup.json
index 8671f8a9dca7..28e23a327026 100644
--- a/specification/network/resource-manager/Microsoft.Network/stable/2019-02-01/networkSecurityGroup.json
+++ b/specification/network/resource-manager/Microsoft.Network/stable/2019-02-01/networkSecurityGroup.json
@@ -627,13 +627,12 @@
         },
         "protocol": {
           "type": "string",
-          "description": "Network protocol this rule applies to. Possible values are 'Tcp', 'Udp', 'Icmp', 'Esp', 'Ah', and '*'.",
+          "description": "Network protocol this rule applies to. Possible values are 'Tcp', 'Udp', 'Icmp', 'Esp', and '*'.",
           "enum": [
             "Tcp",
             "Udp",
             "Icmp",
             "Esp",
-            "Ah",
             "*"
           ],
           "x-ms-enum": {