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kdw313's avatar
Icon for Nimbostratus rankNimbostratus
Jun 29, 2023

Questions about performance degradation when used with DNS features in GTM solutions

Hi team.

Here's the situation I'm in and the questions I have.

Situation : A customer is using Window DNS, and in this configuration, an F5 device has been introduced for GSLB purposes.

However, the performance of Window DNS is not good, so I am checking if it is possible to use the DNS function on the F5 device introduced for GSLB.

Q: I have heard that the performance of the F5 GTM solution degrades when used for DNS functions other than GSLB (I heard from someone that the performance degrades a lot when using BIND).

So, I've been looking for official F5 documentation to see if that's true, but I'm not finding it, so I'm asking.


3 Replies

  • xuwen's avatar
    Icon for Cumulonimbus rankCumulonimbus

    Using dns express as a slave dns server, but dns express has a disadvantage that it does not perform recursive queries(such as NS or cname, recursion will not work if a request is made for a delegated sub-domain if the parent domain exists in DNS Express)  and needs to be combined with iRules. When performing recursive queries, disable dns express and roll back to the bind function for recursive queries

    • kdw313's avatar
      Icon for Nimbostratus rankNimbostratus

      Thank you for your response.

      However, the gist of my question is related to performance degradation when using GTM devices for DNS purposes.


  • Hello,

    As xuwen mentioned, DNS express will be a good fit for you as it is the next feature selected if GSLB is not matched.

    There is a hierarchical mechanism on GTM for resolving queries. The first match is GSLB, the second one is DNS express, and the third option is a caching layer.

    I believe using any of the above options will not have a negative impact on the performance of F5.

    other options are load-balancing DNS requests to a DNS server behind the GTM, and then using the BIND DNS on GTM. So try making use of the GTM features like DNS express, GSLB, and caching layer.