> For the complete documentation index, see [llms.txt](https://help.security.gallagher.com/knowledge-hub/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.security.gallagher.com/knowledge-hub/products/cc-hardware/controllers/controller-6000/configure/controller-6000-dynamic-dns.md). # Dynamic DNS Configure Controller 6000 DNS failover for backup Command Centre servers. The DNS setting allows the use of **Domain Name Servers (DNS)** in disaster recovery situations, especially where backup servers reside on different subnets. ## Failover behaviour If DNS is configured: if the Server stops responding for at least **10 minutes**, the controllers will start querying the specified DNS servers in order and try to connect to the listed IP address. If it cannot connect, the controller continually cycles through the DNS servers. Once it connects to the Server, it will **stay with this server until the connection is lost for 10 minutes**, where it will again query the DNS servers, starting with the **primary server**. ## How CC uses DNS records The controller is looking for the **Server CNAME** on the DNS server, which then points to the **A record** (which contains the server's IP address). > ⚠️ **A-record maintenance:** The A record must be **manually updated** to point to the server's new IP address (unless the site has Dynamic DNS configured) before the controllers will be able to find the backup server. > ⚠️ **FQDN match:** The backup server **must use the same FQDN** as the production server. *** The DNS failover behaviour is identical between the C6000 and the C7000. See the C7000 equivalent at [Controller 7000 - Dynamic DNS](/knowledge-hub/products/cc-hardware/controllers/controller-7000-and-7000-sdc/configure/controller-7000-dynamic-dns.md). *** 🔗 **Related** * [Controller 7000 - Dynamic DNS](/knowledge-hub/products/cc-hardware/controllers/controller-7000-and-7000-sdc/configure/controller-7000-dynamic-dns.md). The same behaviour on the C7000. * [Bringing online and networking](/knowledge-hub/products/cc-hardware/controllers/controller-6000/configure/controller-6000-bringing-online-and-ne.md). The wider networking workflow. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://help.security.gallagher.com/knowledge-hub/products/cc-hardware/controllers/controller-6000/configure/controller-6000-dynamic-dns.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.