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Instruct BIND to not use EDNS

Discussion in 'Bind / DNS / Nameserver Issues' started by pyraetos, Jan 5, 2017.

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  1. pyraetos

    pyraetos Registered

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    For a project I'm examining the behavior of recursive DNS servers, right now BIND servers in particular. By having access to both the asker and the BIND server "A", I can ask BIND to query another server "B" on my behalf and use Wireshark to see what is going on. It seems that BIND by default includes EDNS fields under Additional in its message to B, but depending on what "B" is running, it might not support EDNS. So BIND gets an error in response and moves on to its contingency plans which include sending the same query with no EDNS.

    I was wondering if there was a way to instruct A from the asker to skip EDNS altogether. (It can be disabled by the owner of A, but in practice we will not have access to this server). I thought there might be some obscure option I could include in the asker's initial packet under Additional to tell BIND to "skip" that stuff. I have read that sending it over TCP could also be a way to avoid this behavior. Thanks in advance for any ideas!
     
  2. cPanelMichael

    cPanelMichael Forums Analyst
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    Hello,

    I don't believe this is possible without access to the server, however this is more of a system administration task that you may receive more feedback from on a website such as StackOverflow. Or, you may want to consult with a qualified system administrator from one of the companies listed at:

    System Administration Services | cPanel Forums

    Thank you.
     
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