diff --git a/azurerm/helpers/validate/network.go b/azurerm/helpers/validate/network.go
index 99a88e2d841e..390d5721f679 100644
--- a/azurerm/helpers/validate/network.go
+++ b/azurerm/helpers/validate/network.go
@@ -53,7 +53,7 @@ func PortNumber(i interface{}, k string) (_ []string, errors []error) {
 		return
 	}
 
-	if v < 0 || 65535 < v {
+	if v < 1 || 65535 < v {
 		errors = append(errors, fmt.Errorf("%q is not a valid port number: %q", k, i))
 	}
 
diff --git a/azurerm/helpers/validate/network_test.go b/azurerm/helpers/validate/network_test.go
index 56cbe62eacd4..b2e91fdd7bb5 100644
--- a/azurerm/helpers/validate/network_test.go
+++ b/azurerm/helpers/validate/network_test.go
@@ -162,7 +162,7 @@ func TestPortNumber(t *testing.T) {
 		},
 		{
 			Port:   0,
-			Errors: 0,
+			Errors: 1,
 		},
 		{
 			Port:   1,