421 4.4.2 service timed out
Article ID: 276539
Updated On:
Products
Issue/Introduction
When attempting to deliver messages to Messaging Gateway (SMG), some connections are closed with the 421 4.4.2 service timed out response.
Cause
Messaging Gateway has a default idle session timeout of 30 seconds. If an SMTP connection to SMG is opened but is left idle for more than 30 seconds then SMG will respond on that connection that the SMTP service had timed out and that the connection should be reattempted.
- Some intermediate network device may be scanning or otherwise interfering with the SMTP connection
- If DLP is being used in reflect mode, the DLP server may be taking longer to scan the message than the SMTP session
timeout - Some mail servers use a form of connection cacheing which holds an idle network connection open for longer than the Messaging Gateway session timeout
Resolution
Closing idle SMTP connections is normal Messaging Gateway operation and intended to conserve resources which might be otherwise be consumed by idle SMTP connections.
While Broadcom Support does not recommend modifying the default session timeout, this configuration value may be adjusted using the Administration > Configuration > hostname > SMTP > Advanced Settings page for the appropriate tab for the SMTP listener / interface or for the delivery MTA.
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