DNS Lookup Fail with Amazon DNS Server

Question

Hello,  
  
I'm running into an issue where executing nslookup of an external domain (DNS hosted outside of AWS) is failing intermittently.   
  
The output I get from nslookup is:  
Error checking DNS for (domain)  
Server:         10.0.0.2  
Address:        10.0.0.2#53  
  
** server can't find (domain): SERVFAIL  
  
My DHCP options include: domain-name-servers = AmazonProvideDNS  
  
Please let me know what other info I can supply to help troubleshoot this.  
  
Best Wishes,  
Justin

Answer

Hello Justin,  
  
As per the VPC configuration, AWS provided DNS server "10.0.0.2" is the DNS resolver for your VPC. However, generally the status "SERVFAIL" is set by the Name Server (NS) of the domain and not the resolver.   
  
SERVFAIL: Server failure—the name server was unable to process this query due to either a problem with the name server or a requested feature that can’t be satisfied due to configuration problems.  
  
Therefore, I would recommend to check if there is a misconfiguration on the Name Server end.   
  
In order to isolate the intermittent "servfail", run multiple dig queries on the different Name Servers for the domain.   
1. Find all the Name servers for your domain "dig  NS"  
2. Run multiple dig on each of the Name servers : "dig  @"  
  
The intermittent failure could be due to one of the multiple Name Servers having issues with it. Identify the name server who is setting the servfail status and report it to your DNS Hosted Zone provider.

DNS Lookup Fail with Amazon DNS Server

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