- Products
- Network Security
Next Generation FirewallNext-generation firewall for SMB, Enterprise, and Government
Security ServicesComprehensive security for your network security solution
Network Security ManagerModern Security Management for today’s security landscape
- Advanced Threat Protection
Capture ATPMulti-engine advanced threat detection
Capture Security applianceAdvanced Threat Protection for modern threat landscape
- Access Security
Cloud Edge Secure AccessDeploy Zero-Trust Security in minutes
Secure Mobile AccessRemote, best-in-class, secure access
Wireless Access PointsEasy to manage, fast and secure Wi-FI
SwitchesHigh-speed network switching for business connectivity
- Email Security
Email SecurityProtect against today’s advanced email threats
- Cloud Security
Cloud App SecurityVisibility and security for Cloud Apps
Cloud Firewall (NSv)Next-generation firewall capabilities in the cloud
- Endpoint Security
Capture ClientStop advanced threats and rollback the damage caused by malware
Content Filtering ClientControl access to unwanted and unsecure web content
- Product Widgets
- Product Menu Right Image
- Network Security
- Solutions
- Solutions Widgets
- Solutions Image Widgets
- Solutions Widgets
- Partners
- Partner Widgets
- Partners Image Widgets
- Partner Widgets
- Support
- Support Widget
- Support Image Widgets
- Support Widget
- Products
- Network Security
- Next Generation FirewallNext-generation firewall for SMB, Enterprise, and Government
- Security ServicesComprehensive security for your network security solution
- Network Security ManagerModern Security Management for today’s security landscape
- Advanced Threat Protection
- Capture ATPMulti-engine advanced threat detection
- Capture Security applianceAdvanced Threat Protection for modern threat landscape
- Access Security
- Cloud Edge Secure AccessDeploy Zero-Trust Security in minutes
- Secure Mobile AccessRemote, best-in-class, secure access
- Wireless Access PointsEasy to manage, fast and secure Wi-FI
- SwitchesHigh-speed network switching for business connectivity
- Email Security
- Email SecurityProtect against today’s advanced email threats
- Cloud Security
- Cloud App SecurityVisibility and security for Cloud Apps
- Cloud Firewall (NSv)Next-generation firewall capabilities in the cloud
- Endpoint Security
- Capture ClientStop advanced threats and rollback the damage caused by malware
- Content Filtering ClientControl access to unwanted and unsecure web content
- Product Widgets
- Product Menu Right Image
- Network Security
- Solutions
- Solutions Widgets
- Solutions Image Widgets
- Solutions Widgets
- Partners
- Partner Widgets
- Partners Image Widgets
- Partner Widgets
- Support
- Support Widget
- Support Image Widgets
- Support Widget
DNS resolution fails with FORMERR after upgrading to 12.3 or 12.4
10/22/2020 
4 People found this article helpful
90,578 Views
Description
The DNS resolution fails over the connect tunnel client or from the AMC lookup feature
Cause
DNS query sent from the SMA device adds the addition EDNS header and this change was made from February 2019 after the DNS flag day update.
After February 1st 2019 major public DNS resolver operators will disable/stop accommodating work around for standards non-compliance responses and will start accepting DNS packets with EDNS extensions under the additional records
Resolution
DNS packages on the SonicWall SMA devices have been updated to accommodate DNS requests with the additional resource records and this change was mainly for the GTO services. This ensures that the SMA appliances under GTO service remain responsive to EDNS queries.
This also affected any query made to the internal DNS server, as an appliance on 12.3 or 12.4 sends a DNS query with additional records to the internal DNS server. If the internal server is not capable of handling DNS packets with additional records, it responds back with a "format error".
Below image is the request from SMA appliance to the DNS server,
Windows server 2008 or 2012 might not handle DNS requests with EDNS records and DNS cookies, this is because EDNS or DNSSEC might note be enabled on the server.
Steps to fix this issue, Run the below command on windows server and enable DNSSEC on the DNS management properties,
--> dnscmd /config/enableednsprobes 1
For more details about DNS flag day, please refer the below link
Related Articles
- Configuring Device Management based on Device ID for SMA 100
- CT with Device Guard is stuck on Identifying when GVC Client is installed
- SMA1000: CT compatibility with 3rd party VPN clients like GVC, Citrix and Fortinet
YES
NO