MS-ISAC Releases Advisory on DNS Flag Day

Original release date: January 30, 2019

The Multi-State Information Sharing & Analysis Center (MS-ISAC) has released an alert on Domain Name System (DNS) Flag Day, which is Friday, February 1, 2019. On DNS Flag Day, DNS software and service providers will roll out updates to remove workarounds that allow users to bypass the Extension Mechanisms Protocol for DNS (EDNS). While the updates will improve DNS operations, some domains served by DNS servers operating out-of-date software may become unavailable.

The National Cybersecurity and Communications Integration Center (NCCIC), part of the Cybersecurity and Infrastructure Security Agency (CISA), encourages users and administrators to review MS-ISAC’s Cyber Alert: DNS Flag Day for more information and the DNS Flag Day website to determine whether a domain name will be affected.


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