Forum Discussion
NimbostratusDNS Failover Mechanism
Apologize for a very basic question. We have one F5 DNS in DC and one in DR. For our domain abc.com, in the service provider, Authoritative DNS is DC DNS & DR DNS. As per my understanding, ISP would be following round robin method for load balancing between the authoritative servers. So, when my DC DNS box is shut down, will client be contacting DC DNS box leading to a timeout?
Please help me understand the concept.
youssef1Cumulonimbus
Hello,
it's not a basic question. On the contrary, it is important that you raised it
I recapitulate. you have 2 dns that are authoritative for your domain abc.com.
ns1.mydomain.com
ns2.mydomain.com
If you F5 DNS Fail (ns1.). it will happen the following way...
User will try to join (he will make a request to his ldns). It all depends on how its dns, iterative or recursive is configured suppose it is iterative:
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User request to his ldns
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ldn request Root Hint (.com)
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then ldn request level hint...
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then ldn request ns1.mydomain.com ns1 dont'answer, ldn wait 1 second then try ns2...
this timeout is differente between windows and Linux system...but in general it is of the order of a few seconds (1s)...
Let me now if it answers your question.
Regards
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Faruk_AYDINRound robin is the default behavior of DNS servers. You must have two records for name server of your domain. One is DC DNS, the other is DR DNS. All requester receive these two records but the order changes every request. For example, in the first response, let DC DNS be the first record, and DR DNS be the second record, as for the second request DC DNS will be the first record, and DR DNS will be the second record.
If DR DNS is down, this means no response, then client tries the other record(DNS), in our example: DR DNS.
That is it.