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] Functionality of the DNS ALG

0

0

Article ID: KB24599 KB Last Updated: 29 Jul 2020Version: 2.0
Summary:

This article provides information about the functionality of the DNS ALG on ScreenOS 6.0 or later.

Solution:

The DNS ALG is different than most of the other protocol ALG’s. There are no secondary connections to be managed; rather, DNS ALG closes the firewall session, as soon as a reply is returned from the DNS server. DNS does not have any session tear down procedure and the sessions will remain, until the protocol time out expires.

The time out needs to be long enough to support the iterative query process, which could be involved. With the ALG in place, completed DNS queries are removed from the session table in a timely manner; without the need to adjust the protocol time out to a level, which could cause issues for slower valid queries.

Modification History:
2020-7-29-: Content reviewed for accuracy. No changes needed
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