Support Support Downloads Knowledge Base Juniper Support Portal Community

Knowledge Base

Search our Knowledge Base sites to find answers to your questions.

Ask All Knowledge Base Sites All Knowledge Base Sites JunosE Defect (KA)Knowledge BaseSecurity AdvisoriesTechnical BulletinsTechnotes Sign in to display secure content and recently viewed articles

[ScreenOS/SRX] Information about the Half-closed timeout feature



Article ID: KB26912 KB Last Updated: 26 Jun 2020Version: 2.0

This article provides information about the half-closed feature and if it is supported on ScreenOS and SRX platforms.

  • TCP, when established, is a bi-directional pipe.

  • A half-closed connection is when the client (or server) sends a FIN and the server (or client) ACKs the FIN, without sending a FIN itself. The timer starts, when this condition is met.

  • Some other devices have the ability to define a half-closed timeout, independent of the TCP timeout.

  • Is this ability also supported on ScreenOS and SRX firewalls?


ScreenOS and SRX based security devices do not support this feature. When a half-closed condition occurs, the side that has the connection open will use the default TCP timeout that is set on the device.

Modification History:
2020-06-26: Article reviewed for accuracy. Article is correct and complete.
Comment on this article > Affected Products Browse the Knowledge Base for more articles related to these product categories. Select a category to begin.

Getting Up and Running with Junos

Getting Up and Running with Junos Security Alerts and Vulnerabilities Product Alerts and Software Release Notices Problem Report (PR) Search Tool EOL Notices and Bulletins JTAC User Guide Customer Care User Guide Pathfinder SRX High Availability Configurator SRX VPN Configurator Training Courses and Videos End User Licence Agreement Global Search