DNS request timed out trying to reach local seconday Windows server DC on VPC



I am looking for some help with servers not being able to reach a secondary DC's DNS server within a VPC. DNS resolution works fine when the primary DC is up, but as soon as that server is down the servers are no longer able to resolve any addresses from the secondary DC/DNS server and they just get the DNS request timed-out error.

I have tested the server's ability to resolve to the DNS server by using nslookup and specifying the secondary DC's IP address and that works fine when the primary is running. The servers are currently using the DHCP option set to specify the DNS servers. I am wondering if I should maybe use fixed DNS servers, but this doesn't really make any sense.

The DC's are members of the same security groups .

Any help would be great. Thanks

2 Answers

I think this may be just down to how windows uses its list of DNS Servers.. Ive seen this before and others report the same behaviour as your question if you google it.

  1. If you can manually point to the 2nd server with NS lookup and it returns IP Addresses then connectivity is good.
  2. So long as you have 2 DNS Servers defined in if you type ipconfig /all in a command prompt and if both DNS servers are listed, then DHCP scope is working..
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answered a month ago

Yes, all seem like very basic DNS server settings. There are 2 DNS servers set up within the server's IP configuration. It has the loopback address first then its own IP and then the other DC. As soon as you turn off the other DC all DNS requests time out and DNS lookups fail. NSlookup says DNS request timed out and the server is unknown. I don't understand why is suddenly can't communicate with the other DC. It is like it passes all requests to the other DC/DNS server and cannot provide any resolution itself. I've never had this problem on any network other than within AWS, just does not make any sense to me

answered a month ago

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