CISCO ISE DNS CONFIGURATION

[lilianamartinez]

Hi ,  I was searching cisco documentation about dns configuration on ISE , I was wondering if we can configure up to 3 DNS on ISE and primary DNS goes down , should ISE try to resolve by the secondary one? Today DNS primary goes down and it lose AD conectivity because of that a lot of user could,t authenticate, so costumer was asking to add a 3rd DNS to avoid this issue again.

[balaji.bandi]

, I was wondering if we can configure up to 3 DNS on ISE and primary DNS goes down , should ISE try to resolve by the secondary one?

yes, i do, but when you configure you need to restart the ISE service to take effect of new DNS Settings ? has this been done?

https://www.cisco.com/c/en/us/td/docs/security/ise/2-1/cli_ref_guide/b_ise_CLIReferenceGuide_21/b_ise_CLIReferenceGuide_21_chapter_011.html

When DNS Fails you can see the Logs in ISE, why it not able to resolve other DNS ? check the Logs ?

[thomas · Accepted solution]

3 DNS servers are supported:

ise/admin# conf t
Enter configuration commands, one per line. End with CNTL/Z.
ise/admin(config)# ip name-server ?
<A.B.C.D>|<valid IPv6 format> Primary DNS server address
<A.B.C.D>|<valid IPv6 format> DNS server 2 IP address
<A.B.C.D>|<valid IPv6 format> DNS server 3 IP address 

[bkatrep]

 thomas. i removed the existing primary dns server ip on ise node and added a new one. i configured the old dns ip as the secondary and restarted the services on the node. But still seeing the DNS requests originating from the old server ip. any clue ? how to check a specific daemon 

[Marcelo Morais]

Hi @bkatrep ,

 please try to reload the Node.

Hope this helps !!!

[ajc]

I added a 3rd entry to ISE CLI DNS configuration and now the Node is completely stuck. See attached picture. I did a reload of the node, it did not help. the difference is that this new DNS server is a new Windows 2019 compare to the original 2 entries that are 2012.