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"exec dns refresh" is not updating DNS names when IP address has changed



Article ID: KB13549 KB Last Updated: 30 Nov 2009Version: 1.0
When using either the "Refresh" button in the WebUI, or the "exec dns refresh" from command line, existing DNS entries aren't updating.
Resolved DNS entries on the firewall aren't updating their TTL, or their IP address (if it has changed), when using the "exec dns refresh" command via CLI, or the "Refresh" button in the WebUI.
If there is a resolved DNS entry in the DNS table on the firewall (with a TTL), clicking the "Refresh" button or using "exec dns refresh" will have no affect.
The solution is to do one of the following:
  1. Wait for the TTL of the DNS entry to expire. Once that happens, the firewall will have to go to the DNS server and find that entry again. If the IP has changed, it will then log that entry into the table on the firewall, and start counting down with another TTL.

  2. OR

  3. Manually remove the DNS entries with the 'clear dns' CLI command.  Then, the next request to go to said website, the firewall will recognize that it doesn't have that entry anymore, and will then query the DNS server for it. Whatever response it gets from the DNS server it logs in the table.
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