Overview
If you find a large number of Domain Name System (DNS) resolution exceptions on your domain names, you can use the DNS traffic analysis feature to find out the main causes of the exceptions. For example, the requested domain name does not exist, or the requested DNS record type does not exist. The statistics on DNS responses in the following states are displayed on the Analysis of Response Characteristics tab: NOERROR, NXDOMAIN, and NXRRSET.
The capability of analyzing DNS response characteristics applies to only domain names with the DNS traffic analysis feature enabled, regardless of whether the domain names are bound to free or paid Alibaba Cloud DNS instances. If you want to view the information about DNS response characteristics, you must enable the DNS traffic analysis feature for desired domain names.
Procedure
Log on to the Alibaba Cloud DNS console.
On the Authoritative Domain Names tab of the Domain Name Resolution page, find the desired domain name and click the line chart icon in the DNS Traffic Analysis column.
On the DNS Traffic Analysis tab, click Analysis of Response Characteristics.
Query data based on specific criteria
Query data by time range
You can query data in a custom time range within the last 90 days. Data collected within the custom time range is aggregated and displayed. The proportions of DNS responses in different states are displayed, and the domain names with negative responses are ranked based on the number of DNS requests in ascending or descending order.
Query data by domain name
By default, the status of DNS responses that correspond to all subdomain names is displayed. You can filter data to view the proportion of DNS responses in different states for a specific subdomain name.
DNS response status
NOERROR: In the request for comments (RFC) naming convention, NOERROR indicates that a query is complete. However, this does not necessarily mean that the requested information exists. To help you distinguish DNS response states in DNS request analysis scenarios of Alibaba Cloud in a more fine-grained way, NOERROR in this topic indicates that a specific DNS record is returned for a DNS request by the authoritative DNS server.
NXDOMAIN: indicates that the queried domain name does not exist. When you query a domain name that is not hosted by the authoritative DNS server, the authoritative DNS server returns NXDOMAIN.
NXRRSET: In the RFC naming convention, NXRRSET indicates that the DNS record you want to update does not exist. To help you distinguish DNS response states in DNS request analysis scenarios of Alibaba Cloud in a more fine-grained way, NXRRSET indicates that a specific type of DNS record, such as an A, AAAA, or MX record, does not exist for the queried domain name, but the domain name exists. Networks that support both IPv4 and IPv6 are gaining increasing popularity. In such networks, many users add only A records for their domain names but clients initiate DNS requests for both A and AAAA records at the same time. In this case, NXRRSET is returned for the DNS requests for AAAA records and correct results are returned for the DNS requests for A records. NXRRSET does not necessarily mean a DNS resolution exception. When NXRRSET is returned, you need to check whether the corresponding type of DNS record is configured.
