When you make a DNS query, the response you get is accompanied by a code describing what happened to the query that was made. These DNS return codes also have short names (DNS return messages) attached to them which helps to easily understand what they mean.
DNS return codes mostly describe what happened to your query when it fails. If your query is successful (which is often the case) you will get the RCODE:0 code whose short name is NOERROR.
DNS return codes for your queries on our network can be seen in the query logs on your site administration dashboard.
Below is a list of the most common DNS return codes you will come across
|DNS Return Code||DNS Return Message||Description|
|RCODE:0||NOERROR||DNS Query completed successfully|
|RCODE:1||FORMERR||DNS Query Format Error|
|RCODE:2||SERVFAIL||Server failed to complete the DNS request|
|RCODE:3||NXDOMAIN||Domain name does not exist|
|RCODE:4||NOTIMP||Function not implemented|
|RCODE:5||REFUSED||The server refused to answer for the query|
|RCODE:6||YXDOMAIN||Name that should not exist, does exist|
|RCODE:7||XRRSET||RRset that should not exist, does exist|
|RCODE:8||NOTAUTH||Server not authoritative for the zone|
Name not in zone
For an exhaustive list of DNS return codes, check out the standard list on the IANA website.