Master, slave, transfer, subdomain, and delegated lab manual for DNS under CentOS

DNS master, slave, transfer, subdomain and assignment lab Manual

Cutting-edge: Understand the following concepts before doing experiments:

1. What is DNS?

DNS stands for the Domain Name System. Simply put, it resolves a Domain Name into an IP address.

2. What types of DNS are there?

Primary Domain Name Server

Secondary Domain Name Server

Forwarding Domain Name Server

Cache Domain Name Server

3. What types of DNS queries are available?

The query methods are divided into recursive queries (either query succeeded or query failed) and iterative queries (query another DNS process from one DNS)

The query content can be divided into forward query (the IP address query process by domain name) and reverse query (the domain name query process with IP addresses)

4. What steps are the DNS resolution sequence generally divided?

First query the DNS cache, then query the Hosts file, and finally query the DNS server.

5. What are the following DNS forwarding rules?

Forward the query that cannot be resolved by the local DNS server to other DNS servers on the Internet. This DNS server is designated as a forwarder and the query by the forwarder is a recursive query.

6. What is the role of the DNS secondary Domain Name Server?

When the primary server is shut down, there is a fault or the load is too heavy, the secondary Domain Name Server provides the domain name resolution service as a backup.

7. What are the following delegation concepts?

When there are too many subdomains in the region, it is inconvenient to maintain them. If you encounter a domain name query bottleneck, you can assign the subdomains to other servers for maintenance by submitting a new deployment committee in the region.

8. What are the differences between subdomain names and delegates?

The subdomain file is in the parent file.

Assign an independent regional File

Lab (1)

Experiment Name: build and test the primary DNS

Objective: To master the primary DNS establishment and client Test

Tutorial topology:

Tutorial steps:

1. Set up the experiment environment based on the experiment topology, where XXX = 10, Linux B is the primary DNS server, and Linux A is the Linux client.

2.1 set up the primary DNS service on LinuxB. First, check whether the DNS service package is installed.

2.2 edit the DNS master configuration file vi/etc/named. conf and copy the 11 lines from the DNS master configuration to the last line of the file.

2.3 edit the last 11 rows and fill in the forward and reverse region files and database files.

2.4 search for regional database files.

2.5 copy the database file to the specified file.

2.6 edit the forward database file vi xapc.com. dns.

2.7 edit the reverse database file vi xapc.com. rev.

2.8 start the DNS service.

2.9 test on Linux A client.

Experiment (2)

Experiment Name: build and test the secondary DNS Service

Objective: To master the test of configuring data synchronization between primary DNS and secondary DNS

Experiment topology: (See Experiment (1 ))

Tutorial steps:

1. set up the experiment environment and build the experiment environment based on the experiment topology. Linux B is the primary DNS server, Linux C is the secondary DNS server, and Linux A is the DNS Client, experiment 2 is built on the primary DNS of Experiment 1.

2.1 set up the secondary DNS service on LinuxC. First, check whether the DNS service package is installed.

2.2 edit the DNS master configuration file vi/etc/named. conf and copy the 11 lines from the DNS master configuration to the last line of the file.

2.3 edit the last 11 lines, that is, configure the secondary DNS server.

2.4 restart the DNS service.

2.5 check whether the primary and secondary DNS data is synchronized on Linux C, that is, whether the secondary DNS service synchronizes data from the primary DNS.

2.6 In Linux, test whether the secondary DNS service can provide the domain name resolution service normally.

Lab (3)

Experiment Name: build and test the forwarding DNS Server

Objective: To master the working principle, configuration, and test of the forwarding DNS Server

Experiment topology: see Experiment (1)

Tutorial steps:

1. set up the experiment environment and build the experiment environment based on the experiment topology. linux B xapc.com and Linux C ctc.com are independent DNS servers, you can configure a DNS server to forward records that cannot be resolved by one DNS server to another.

2.1 set up the DNS service on Linux C. First, edit the primary DNS configuration file.

2.2 edit the forward database file.

2.3 edit the reverse database file.

2.4 start the DNS service and test it on the Linux C client.

2.5 configure a forwarder on Linux B to forward host records not resolved by DNS on Linux B to the DNS server on Linux C, let Linux C provide it with name resolution (the region and IP address of the other party ).

2.6 test the forwarding server configuration. On the client Linux A, specify the DNS server as Linux B, but resolve the host records on Linux C. This indicates that the DNS forwarding configuration is successful.

Note: DNS forwarding can only be resolved to the forward region host records on the forwarding server, but the host records in the reverse region cannot be resolved. This solution solves the problem of host records in the reverse region:

1) if the two DNS servers are in the same network segment, the reverse region cannot be forwarded in the primary DNS configuration file, because the configuration file does not allow two reverse records of the same network segment. Only reverse host records of the other DNS can be appended to the reverse configuration file of the forwarding DNS server.

2) If the two DNS servers are not in the same CIDR block, you can configure the reverse host area like configuring forward zone file forwarding.

Experiment (4)

Lab name: subdomain and its delegation

Objective: To master the concept and configuration of subdomains and their delegation

Experiment topology: (See Experiment 1)

Tutorial steps:

1. Set up the experiment environment. Set up the experiment environment according to the experiment environment. Linux B is the parent domain DNS server, and Linux C is the subdomain DNS server.

2.1 set up a subdomain DNS service on Linux C. First, edit the primary configuration file of the subdomain DNS.

2.2 configure the forward database file for the subdomain.

2.3 configure the reverse database file for the subdomain.

2.4 restart the DNS service.

2.5 Add A subdomain NS record and A record to the region file on the Linux B DNS server to edit the forward database file of the parent domain.

2.6 edit the reverse database file of the parent domain and add the NS and PTR host records of a subdomain.

2.7 restart the DNS server.

2.8 test the subdomain and its delegation on Linux.

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