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MW1's avatar
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May 16, 2012

GTM - DNS question- subdomain



really a DNS question more than a GTM question but hoping I can be given direction.



I need to create records on my GTM in zonerunner for :



in a zone ( )I already have an A record for www (i.e. url is




Do I need to create a subdomain zone of with then a A record in it of www, or can I just create an A record in the main zone which is, or will I be sent to the depths of hell and this is terribly bad practise?



Thanks to anyone who can shed any light on this!




3 Replies

  • George_Watkins_'s avatar
    Historic F5 Account
    Hi MW,



    Don't do it. DNS namespace ( consists of labels delimited by periods. RFC 1912 states that "Allowable characters in a label for a host name are only ASCII letters, digits, and the `-' character." Adding periods to hostname labels will likely cause unexpected results for clients consuming your DNS services.



    In full disclosure, I do this on my home network and it works for my purposes, but I'm the only who uses the DNS server. Definitely not something I would try in a production environment. If you'd like to automate the workload of adding a bunch zone to Zonerunner, consider writing an iControl script. Here is a thread with an example of using iControl to add zone files: Getting Error while using add_zone_file API for creating Management Zone.



  • Thanks for the response - I did test t(doing it the wrong way) on the GTM and it does appear to work as you mentioned, however if you update a record (e.g. change the IP of a A record) it creates a duplicate record in the zone and leaves the old record untouched.



    I am presuming on the GTM's I would simpy define NS records in the main zone ( for the subdomain zone, and then create a new zone in zonerunner to add the A records to?
  • Yes the correct way would be to create the new zone for and would think the NS records would be part of the new zone..