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telco01_122150's avatar
telco01_122150
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Mar 26, 2013

DNS caching

Hi all, new to the F5 environment and devcentral. As i'll be working closely with F5 products i am trying to build my knowledge in the field. Considering im completely new please forgive some of my ignorance.

 

We are looking to replacing our caching DNS servers with a single F5 product. It will hold no authoritative power but merely cache recursive responses from other Authoritative DNS servers as requests flood into it. It is an ISP type environment and will be receiving a huge number of DNS requests. Essentially it is the first point of call for DNS queries for a large client base.

 

My questions are:

 

  • is this possible with F5 products?
  • where can i find in depth documentation on dns with f5 products?
  • what f5 device would best suit such an environment?
  • As i understand there are different dns capabilities within the big-ip range, (transparent, recursive etc), which would best suit this type of scenario?

 

 

Any infromation is greatly appreciated!

 

thanks in advance.

 

 

basic
getting started
new to f5

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  • El_Jefe's avatar
    El_Jefe
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    Mar 26, 2013
    Hello!

     

     

    Yes, what you are looking for is possible with F5 Products.

     

     

    The functionality you are looking for is in GTM, specifically, DNS Express, which is a feature of GTM Version 11. It is basically, a high-speed DNS cache, that serves out DNS requests at a VERY high rate of speed. Depending on the amount of DNS requests needing to be processed, GTM runs on all the BIGIP PLatforms, including the VIPRION blade chassis.

     

     

    Here is an article you might want to take a look at - https://devcentral.f5.com/tech-tips/articles/v11-dns-express-ndash-part-1.UVEcT1eNBc4

     

     

    Hope this helps!

     

     

    Jeff

     

     

  • telco01_122150's avatar
    telco01_122150
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    Mar 26, 2013

    Thanks Jeff. Just to wrap my head around this (im drafting for a few proof of concepts for some F5 products we're looking at) the dns express feature wouldnt be viable on LTM? As always cost is a factor i have to account for, are the vast differences in the capabilities between GTM and LTM? The soul purpose it'll be used for is DNS handling. Would i pick the most suitable chassis then determine whether i would have LTM or GTM loaded on the hardware?

     

  • El_Jefe's avatar
    El_Jefe
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    Mar 26, 2013
    LTM is primarily geared towards local load balancing via full proxy. GTM is primarily focused on Global DNS Load Balancing. When used in conjunction, The GTM receives the DNS requests, and forwards to the local datacenter's LTM depending on the method chosen (global availability, topology, etc. ) I would think that GTM standalone would be the your best option for the solution you are looking at. Once you decide that is the way you want to go, you then select the platform based on the expected load, factoring in for future growth.
  • enordquist_1378's avatar
    enordquist_1378
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    Nov 25, 2015

    Did you ever end up implementing caching on the F5? We are in the process of doing this and would love to talk to others who have done it already