Sunday, March 11, 2018

DNS resolution for Cisco Catalyst Switch sourced on a VRF?

I'm trying to accomplish the following:

  • The default routing table doesn't actually route anywhere. There are no interfaces or SVIs on the default routing instance.
  • The "Management" vrf can route to the management-ey-things and can ping the internet.
  • The switch can resolve DNS sourcing traffic from the "management" vrf.

Configuration:

vlan 10 int vlan 10 ip address 10.0.0.2 255.255.255.0 ip route 0.0.0.0 0.0.0.0 10.0.0.1 ip name-server 8.8.8.8 

Test:

ping 8.8.8.8 !!!!! ping google.com Translating "google.com"...domain server (8.8.8.8) !!!!! 

Configuration:

ip vrf Management vlan 10 int vlan 10 ip vrf forwarding Management ip address 10.0.0.2 255.255.255.0 ip route vrf Management 0.0.0.0 0.0.0.0 10.0.0.1 ip name-server vrf Management 8.8.8.8 

Tests:

ping vrf Management 8.8.8.8 !!!!! ping vrf Management google.com Translating "google.com"...domain server (255.255.255.255) % Unrecognized host or address, or protocol not running. 

So, It's clearly working when the default routing instance can reach 8.8.8.8 and the name-server client is sourcing it's traffic from the default routing instance, but I can't get it to work when the named Management VRF is sourcing the traffic.

I also find it suspicious that on the "Translating "google.com"...domain server" line, the first configuration shows the IP of the DNS server, and the second configuration shows 255.255.255.255.

Thoughts?

What do I need to do to be able to make this work:

ping vrf Managment google.com 


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