Learn DNS Series (eight) DNS client query process

DNS client registration information in the DNS server is reflected in the way, then the client can use some way to query all kinds of records. Corresponding, the server will respond to these queries, we call it parsing, as for the internal work mechanism of DNS, we do not know, but we can through some commands and methods to understand the DNS query process indirectly. To better describe this problem, I made a simple topo diagram where DNS1 is a DNS server and host XP3 is a DNS client. The topology map is as follows:

When a client submits a query message to a DNS server, it usually contains 3 basic information, 1, the DNS domain name that needs to be queried, 2, specifies the basic type of query request, and 3, the specified category of DNS domain name. For a DNS server for Windows systems, the third is the DNS domain name of the specified category is always the Internet, that is, we often say in the category, whether in the forward or reverse zone DNS files can be seen, we take forward lookup zone DNS file as an example, the following figure:

So, usually we just need to include the DN s domain name and the type of query request when we submit a query, we can explain it by an example. There are 2 A records in the A.com area, as shown below:

So we're querying DNS1 's a record on XP3. To better understand the whole process, we will still use Wireshark to assist with the analysis. The whole process is shown as follows: