Can you please resolve this as I would like to post the following message, thanks very much
Hello, can someone kindly help me with the following question, thanks
I am not a network or F5 person but a Microsoft Server/AD engineer
We want to improve the reliability of our DNS infrastructure as Microsoft Windows Client computers are not particular intelligent when it comes to realizing their primary DNS Server is down and using the alternative ones listed in their config.
So I was thinking why not make the primary DNS IP address more reliable by pointing it to an F5 VIP (where the F5 has its own DR capabilities e.g. F5 farm or what ever the correct term is)
For this to work better than the current solution (where the clients point direct to the DNS Server), I also want the F5 to periodically (every several seconds if possible) to probe the back end DNS Servers to ensure they are not only still alive but can resolve a simple DNS query (meaning they can still service a forward request from a client) e.g. a health prob from the F5 to each DNS Server in the back end DNS Server pool. If a particular DNS Server is not responding as expected direct the DNS query to another of the back end DNS Servers in the DNS pool. Ideally if this health prod picked up an issue to also send an email to one or more email address with a message denoting the failed DNS Server.
Is the above, something can be done, or has been done before (would seem like a logical use for F5s) and if so are they any gotchas or issues one should be aware of?
Thanks very much in advance
What you've described is all doable with BigIP LTM. This includes e-mail alerting in case of Pool Member status changes.
For a performance gain, you should also look into Transparent DNS caching feature. This is available in DNS module. (Ref Doc - section 2)
Thanks very much for taking the time to reply Hannes, much appreciated