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Beginner

Cisco 9500 as DNS Server problem

Hello.

 

In my fabric network cisco 9500series stack is acting as Fusion. I have configured DNS Server on it to server as proxy to my clients. Last 3 days we have been doing migration to office and I had to change 9500 and reconfigure from 0 again and upgraded image to cat9k_iosxe.16.12.04.SPA.bin.

 

The problem is now DNS is not working on clients, they have to use 8.8.8.8 directly. I tried pinging some global domains from switch itself, which works fine but users` request are not processed.

 

There is not any firewall between as I imported switch loopback into VRFs and back. 

 

This is configuration i tried first:

ip domain name XYZ.local
ip domain-lookup
ip name-server 8.8.8.8 8.8.4.4
ip dns server

ip host dnac.XYZ.local 192.168.xxx.yyy

Then I tried to do DNS Forwarding with new way:

ip access-list standard DNS_PERMIT
 permit 192.168.0.0 0.0.255.255

ip dns name-list 1 permit .*

ip dns view default
 domain name-server 8.8.8.8
 domain name-server 8.8.4.4
 domain name XYZ.local
 dns forwarding source-interface Loopback0

ip dns view-list LAN
 view default 1
  restrict source access-group DNS_PERMIT
  restrict name-group 1

ip dns server view-group LAN
ip dns server

None of above helped. Users can even query the local binding which defined in switch with "ip host". Clients can ping switch`s loopback address which is used as dns server. And again from switch I can ping all the domains.

 

What can be the reason?

2 REPLIES 2
Highlighted
Cisco Employee

Hi

 

Since users are part of VRF, are you injecting a default route into VRF table?  All the above configs are part of GRT, which is fine, but hope the route leaking on the fusion is taken care off?

Highlighted

Hi

Yes, route leak is in place as same IP is serving DHCP and DHCP is working fine. I think problem is related to switch not forwarding dns queries coming to it.

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