For more information regarding the security incident at F5, the actions we are taking to address it, and our ongoing efforts to protect our customers, click here.

Forum Discussion

Teerarat's avatar
Teerarat
Icon for Cirrostratus rankCirrostratus
Aug 21, 2017

How does client work when dns response cname to client

I have some problem, I setup F5 DNS response cname when client request dns to > cname: , I try to packet capture when dns response cname to client, I found client not resolve cname, when i try to test by use client request dns to > AD DNS > F5 DNS it's work.

 

application delivery
BIG-IP DNS

1 Reply

  • Stanislas_Piro2's avatar
    Stanislas_Piro2
    Icon for Cumulonimbus rankCumulonimbus
    Aug 21, 2017

    Hi,

     

    Dns client will not follow cname. It send a request and expect a response including all information required.

     

    The dns forwarder (AD) will request his forwarder or root servers.

     

    If the AD uses a forwarder, it works as a dns client, else, it read response and follow NS, CNAME.. until it receive an error or the expected answer (ex : ip address of the resource)

     

    When it get it, it reply to the dns client.