---
title: "Editing DNS Servers"
canonical: "https://docs.infoblox.com/space/BloxOneDDI/186336201/Editing%20DNS%20Servers"
format: markdown
---
The DNS servers cannot be created from **Network** > <span style="color: #000000">**DNS**</span> ><span style="color: #000000">** DNS Servers**</span>. However, you can edit certain details of an existing DNS server. 

<span style="color: #000000">To edit the details of an existing DNS server, complete the following:</span>

1. From the Infoblox Portal, click **Network** > <span style="color: #000000">**DNS**</span> ><span style="color: #000000">** DNS Servers**</span>.
2. <span style="color: #000000">Click </span>☰ <span style="color: #000000">and select </span><span style="color: #000000">**Edit **</span><span style="color: #000000">for a single DNS server. </span>
3. <span style="color: #000000">On the </span><span style="color: #000000">*Edit DNS Server *</span><span style="color: #000000">page, configure the following:</span>
  - <span style="color: #000000">**Name**</span><span style="color: #000000">: The name of the service instance is read-only and cannot be edited. </span>
  - <span style="color: #000000">**Service Instance IP Address**</span><span style="color: #000000">: The IP address of the service instance is read-only and cannot be edited. </span>
  - <span style="color: #000000">**Description**</span><span style="color: #000000">: Additional information about the service instance. This cannot be edited.</span>
  - <span style="color: #000000">**DNS Config Profile**</span><span style="color: #000000">: Choose a DNS configuration profile from the list. </span>
  - <span style="color: #000000">**DNS Name**</span><span style="color: #000000">: Specify a name for the DNS server. </span>
  - <span style="color: #000000">**TAGS**</span><span style="color: #000000">: Tags are read-only and cannot be edited.</span>
  - <span style="color: #000000">In the </span><span style="color: #000000">**GSS-TSIG CONFIGURATION**</span><span style="color: #000000"> section, click </span><span style="color: #000000">**Add**</span><span style="color: #000000"> and choose one of the following options:</span>
    - <span style="color: #000000">**New GSS-TSIG Keytab File**</span><span style="color: #000000">: Click </span><span style="color: #000000">**Select File**</span><span style="color: #000000">, find the keytab file, and click </span><span style="color: #000000">**Add**</span><span style="color: #000000">.</span>
    - <span style="color: #000000">**Existing GSS-TSIG Keytab File**</span><span style="color: #000000">: Select the keytab file from the drop-down, and click </span><span style="color: #000000">**Add**</span><span style="color: #000000">. The following read-only information is shown:</span>
      - <span style="color: #000000">**PRINCIPAL**</span><span style="color: #000000">: The principal name that is mapped to the keytab file</span>
      - <span style="color: #000000">**DOMAIN**</span><span style="color: #000000">: The name of the domain that is mapped to the keytab file</span>
      - <span style="color: #000000">**VERSION**</span><span style="color: #000000">: The version of the keytab file</span>
      - <span style="color: #000000">**ENCRYPTION TYPE**</span><span style="color: #000000">: The encryption type of the key</span>
      - <span style="color: #000000">**LAST UPDATED**</span><span style="color: #000000">: The timestamp of the key's last upload</span>
    - <span style="color: #000000">**Enable Fault Tolerant Caching**</span><span style="color: #000000">: </span><span style="color: #172b4d">Select the check box to enable the DNS Server (NIOS-X Server) to respond to DNS queries when the server is down. When you enable this option, the DNS server (NIOS-X Server) retains the expired records in the recursive cache. Whenever recursive queries times out or returns a SERVFAIL response, the NIOS-X Server returns the cached response to the client instead of the SERVFAIL response. The NIOS-X Server also queries the upstream server after returning the cached response regardless of the query timing out or not. This option is disabled by default. </span><span style="color: #292a2e">When you enable </span><span style="color: #172b4d">DNS fault tolerant cache, you can also specify the TTL (time-to-live) and timeout settings for the expired records. TTL specifies the time duration for which the expired record is retained in the recursive cache. Setting a high TTL might cause the client to use incorrect data for a longer duration. Conversely, setting a low TTL renders more current cached data, but also increases the traffic on your network. The expired record is deleted from the recursive cache after the specified timeout duration. For more information, see </span><span style="color: #172b4d">*[Best Practices for Fault Tolerant Caching](https://infoblox-docs.atlassian.net/wiki/spaces/BloxOneDDI/pages/1466794059)*</span><span style="color: #172b4d">. </span>
      - <span style="color: #000000">**Expired Record TTL**</span><span style="color: #000000">: Specify the time duration that the DNS server must serve the expired records from the recursive cache before attempting to refresh the records. The default is five seconds. Select the time period in minutes, hours, or days from the drop-down list.</span>
      - <span style="color: #000000">**Expired Record Timeout**</span><span style="color: #000000">: Specify the time duration that the DNS server waits before deleting the expired records from recursive cache. The default is 24 hours. Select the time period in minutes, hours, or days from the drop-down list.</span>
4. <span style="color: #000000">Click </span><span style="color: #000000">**Save & Close**</span><span style="color: #000000"> to save the details or click </span><span style="color: #000000">**Cancel**</span><span style="color: #000000"> to exit.</span>


> ℹ️ When Fault Tolerant Caching (FTC) is enabled and a recursive query is initiated via zone delegation, the recursive query is processed before returning the stale cache response. If the delegation DNS server is unresponsive, the response may be delayed by up to 10 seconds.

> ⚠️ If you have enabled DNS Forwarding Proxy, the following message is shown when editing DNS servers:
> ⚠️ 
> ⚠️ <span style="color: #000000">**Universal DDI is currently forwarding to DNS Forwarding Proxy.**</span>