# FirewallSyncReason
<a name="API_FirewallSyncReason"></a>

Describes why a firewall is out of sync. Exactly one of `missingFirewall` or `invalidFirewall` is set.

## Contents
<a name="API_FirewallSyncReason_Contents"></a>

**Important**  
This data type is a UNION, so only one of the following members can be specified when used or returned.

 ** invalidFirewall **   <a name="networksecuritymanager-Type-FirewallSyncReason-invalidFirewall"></a>
Details about a firewall whose configuration does not match the intended configuration.  
Type: [InvalidFirewallReasons](API_InvalidFirewallReasons.md) object  
Required: No

 ** missingFirewall **   <a name="networksecuritymanager-Type-FirewallSyncReason-missingFirewall"></a>
Indicates that an expected firewall is missing. The value describes the missing firewall.  
Type: String  
Required: No

## See Also
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For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\+\+](https://docs.aws.amazon.com/goto/SdkForCpp/network-security-manager-2025-10-30/FirewallSyncReason) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/network-security-manager-2025-10-30/FirewallSyncReason) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/network-security-manager-2025-10-30/FirewallSyncReason)