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F5_324021
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Oct 13, 2017

GTM Response for Virtual Server

Hello,

 

My scenario here is a GTM hosting the application with private IP addresses.

 

And i need the GTM to hold the external DNS queries,

 

Which means once an internet client requests to visit , the external DNS delegating this domain to our GTM, which the delegation is pointing to the public IP address configured on the firewall and mapped to the private self ip address of the GTM.

 

so once the DNS request reaches the GTM it should pick a VS to handle the job for the client requesting the page.

 

My question here is about the DNS response of the GTM to the external DNS , How the GTM will know the Public IP address of this virtual server to tell the external DNS that this is the IP address so the client can use to view page.

 

Hope you can help me in that :)

 

Thanks again

 

2 Replies

  • Create an address datagroup where in each entry the private virtual server IP address is the name and the public NAT address for the virtual server is the value. Apply the following to the LTM virtual server that was created by GTM as the listener.

    when DNS_RESPONSE {
      foreach rr [DNS::answer] {
        if {[DNS::type $rr] ne "A"} { continue }
        if {[class match [DNS::rdata $rr] equals private_vips]} {
          DNS::rdata $rr [class lookup private_vips]
        }
      }
    }
    

    This has to be implemented on every GTM in the sync group.

  • The BIG-IP supports translated addresses for virtual servers but you have to add them manually. This means you have to disable auto discovery. When you add them enter the NAT address in the translate field. Article K9138 discusses this specifically.