Sub-Domain Delegation GTM/DNS

 

Lets say that you have domain.com hosted with a 3rd party DNS provider and you would like to create GTM (BigIP-DNS) DNS load balancing by utilizing Sub-Domain Delegation.

In this scenario, there are 2 GTM. One in each DC (DC-1 & DC-2). The basic set up has been completed and the GTMs are in a common sync-group.

Create A-Records for the 2 GTM using their Listener IP addresses:

 gtm1.wip.domain.com. IN A 100.100.100.100
 gtm2.wip.domain.com. IN A 200.200.200.200

gtm1 and gtm2 exist in DC-1 and DC-2 respectively and 100.100.100.100 & 200.200.200.200 are the listener IP address configured on gtm1 and gtm2.

Delegate the sub-domain to the GTM using NS Records:

 wip.domain.com. IN NS gtm1.wip.domain.com.
 wip.domain.com. IN NS gtm2.wip.domain.com.

Use CNAME records:

www.domain.com. IN CNAME www.wip.domain.com.

The above DNS records (A, NS & CNAME) will be added to the 3rd party DNS records that is hosting domain.com. Any request for

www.domain.com

will be sent to the 3rd party DNS provider which will then resolve to

www.wip.domain.com

because of the CNAME and that will be handled by the GTMs because of the NS & A records.

SOL277 – Sub-domain delegation.

8 Replies to “Sub-Domain Delegation GTM/DNS”

  1. Hope you can help here. Need to create a sub domain in F5 GTM and delegate the zone to 3rd party NS.

    F5 is the SOA for the domain xyz.com. 3rd party wants to manage host records for the sub domain from their NS. Sub domain is test.xyz.com.

    Hope you can help point out the steps involved here. Thanks

  2. In the example that I provided, replace “domain” with “xyz” and replace “www” with “test”:

    A Records:
    gtm1.wip.xyz.com. IN A 100.100.100.100
    gtm2.wip.xyz.com. IN A 200.200.200.200

    NS Records:
    wip.xyz.com. IN NS gtm1.wip.xyz.com.
    wip.xyz.com. IN NS gtm2.wip.xyz.com.

    CNAME:
    test.xyz.com. IN CNAME test.wip.xyz.com.

    Create “test.wip.xyz.com” in the GTM.

  3. Does the subdomain have to be created as a master zone on the F5 that is the SOA for xyz.com? The subdomain would be “test.xyz.com”

    In the A records section, shouldn’t the WIP be “test” instead?

    Because the F5 is doing the delegation should the NS records be pointing to the 3rd party NS instead that is cloud based? They are not using GTM

  4. In this particular case, GTM does not have any DNS files configured. GTM relies on an external DNS provider. All the DNS records exist in a non-GTM environment.

    For example, you can have the DNS records (A, NS, CNAME) at Rackspace or Amazon or any other DNS provider.

    Client makes a DNS query to “test.xyz.com” which goes to the 3rd party DNS provider. The 3rd party DNS provider will utilize the A and NS record to provide the GTM information to the client. Client will query the GTM for “test.wip.xyz.com” and the GTM will respond with the IP of the VS that has the resources for “test.xyz.com”. I will try to add a diagram to clarify the process in 1-2 days.

    In short, I think you are trying to configure DNS records on the GTM but my example is about delegating the DNS records to a 3rd party DNS provider.

  5. Hi mavenet. I’m not having success in following your steps. Hope you can provide some guidance.

    My goal is for the GTM to LB apps.mysite.com

    On mysite.com DNS I have the following…
    wip.mysite.com. IN NS gtm1.wip.mysite.com.
    gtm1.wip.mysite.com. IN A 172.20.253.154
    apps.mysite.com. IN CNAME apps.wip.mysite.com.

    172.20.253.154 is the listener IP on the GTM
    apps.wip.mysite.com is a A record WIP on the GTM

    nslookups and digs fail for apps.mysite.com

    To help my understanding, when a client requests apps.mysite.com, is it that the DNS tell the client to query 172.20.253.154 for apps.wip.mysite.com or the DNS does it on behalf of the client? I ask as my DNS is on a public network and GTM on private, but the client can route to both but the DNS cannot reach the private. Yes, I know, a weird lab setup!

  6. @Keith – LDNS makes the queries. Please, see if the diagram is of any help in clarifying. You should already have DNS configured for mysite.com in a 3rd part DNS provider.

Leave a Reply