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This article mainly introduces "how to build DNS server under RHEL5". In daily operation, I believe many people have doubts about how to build DNS server under RHEL5. Xiaobian consulted all kinds of information and sorted out simple and easy operation methods. I hope to help you answer the doubts about "how to build DNS server under RHEL5"! Next, please follow the small series to learn together!

Domain name and domain name resolution

In order to distinguish each host in the network, each host must be assigned a unique address, which is called "IP address." But these numbers are hard to remember, so they are replaced by "domain names." Eventually, however, the domain name must be translated to the corresponding IP address to access the host.

DNS service, also known as domain name resolution service, provides domain name and IP address conversion. Forward domain name resolution is the process of converting a hostname into an IP address, and reverse domain name resolution is the process of converting an IP address into a hostname. Usually we rarely need to translate IP addresses into hostnames, i.e. reverse resolution. Reverse parsing is often used by background programs that are invisible to the user.

II. DNS architecture

The hierarchy of domains is like an inverted tree, and the hierarchy is very clear. The root domain is located at the top, and immediately below the root domain are several *** domains, each *** domain can be further divided into different secondary domains, and the secondary domain can be further divided into sub-domains. Under the sub-domains, there can be hosts or sub-domains that can be further divided until the *** host. Domain management in the Internet is performed by InterNIC, and domain name services are performed by DNS.

DNS Resolution Process

1. Client request parsing

www.exmaple.com.cn IP address, if there is no relevant resolution in the local hosts file, send a resolution request to the local DNS server;

2. If the local DNS server has resolution information for the domain name, it directly returns it to the client; if the local DNS server does not have resolution information for the domain name, the local DNS server queries the root DNS server for the IP address of www.exmaple.com.cn;

3. If the root DNS server has resolution information of the domain name, it directly returns the information to the local DNS server, and the local DNS server returns the resolution information to the client; if the root DNS server does not have resolution information of the domain name, it returns the IP address of the DNS server governing the.cn resolution service;

4. The local DNS server queries the DNS server that administers.cn for the IP address of www.exmaple.com.cn;

5. If the.cn server has resolution information of the domain name, it directly returns the information to the local DNS server, and the local DNS server returns the resolution information to the client; if the.cn DNS server does not have resolution information of the domain name, the DNS server governing the.cn resolution service informs the IP address of the DNS server of. com. cn;

6. The local DNS server queries the DNS server that administers. com for the IP address of www.exmaple.com.cn;

7. If the.com.cn server has resolution information for the domain name, it directly returns the information to the local DNS server, and the local DNS server returns the resolution information to the client; if the.com.cn DNS server does not have resolution information for the domain name, the DNS server governing the.com.cn resolution service informs the IP address of the DNS server of. example.com.

8. The local DNS server queries www. example.com.cn IP address;

9. The DNS server that administers. example.com informs the IP address of the DNS server that administers www.exmaple.com.

10. The local DNS server resolves the IP address of www.exmaple.com.cn and returns it to the client.

Fourth, build DNS multi-domain resolution server under Linux

RedHat Enterprise Linux 5 update3

Kernel version: 2.6.18-128.el5

DNS Server IP: 192.168.2.210

Web Server A:

www.chinaunix.net

192.168.2.181

Mail server B: mail.chinaunix.net 192.168.2.182

Web Server C:

www.chinaunix.org

192.168.2.183

Mail Server D: mail.chinaunix.org 192.168.2.185

At this point, the study of "how to build a DNS server under RHEL5" is over, hoping to solve everyone's doubts. Theory and practice can better match to help everyone learn, go and try it! If you want to continue learning more relevant knowledge, please continue to pay attention to the website, Xiaobian will continue to strive to bring more practical articles for everyone!

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