The DNS Server is a Domain Name System or Domain Name Service, and RHEL 5 is a System with many applications. Therefore, it is very important for RHEL 5 to build a DSN server, the following is a detailed explanation of how RHEL 5 builds a DNS server.
1. Set up DNS server domain name and domain name resolution in RHEL 5
In order to differentiate each host in the network, a unique address must be assigned to each host. This address is called an "ip address ". However, these numbers are hard to remember, so they are replaced by domain names. However, you must convert the domain name to the corresponding IP address to access the host.
The DNS service, also known as the domain name resolution service, provides mutual conversion between domain names and IP addresses. Forward resolution of a domain name is the process of converting the host name into an IP address. Reverse resolution of a domain name is the process of converting the IP address into a host name. Generally, we seldom need to convert the IP address to the host name, that is, reverse resolution. Reverse resolution is often used by some background programs and is invisible to users.
Ii. Build a DNS server architecture with RHEL 5
The hierarchical structure of the domain is like the same inverted tree, and the hierarchy is very clear. The root domain is located at the top, followed by several top-level domains under the root domain. Each top-level domain can be further divided into different second-level domains, and the second-level domain can be further divided into subdomains, the subdomain can be either a host or a subdomain that can be further divided until the last host. Domain names in the Internet are managed by InterNIC, and domain name services are implemented by DNS.
Iii. DNS Server Resolution Process for RHEL 5
1. The client requests to resolve the IP address of www.exmaple.com.cn. If there is no resolution in the local hosts file, the client sends a resolution request to the local DNS server;
2. If the local DNS server has the resolution information for this domain name, it will directly return it to the client. If the local DNS server does not have the resolution information for this domain name, the local DNS server will ask the root DNS server for www.exmaple.com.cn
IP address;
3. If the root DNS server has the resolution information for this domain name, the system will directly return the information to the local DNS server, and the local DNS server will then return the resolution information to the client; if the root DNS server does not have the resolution information for this domain name, it will return the jurisdiction. cn resolves the IP address of the DNS server of the business;
4. The local DNS server requests the IP address of www.exmaple.com.cn from the DNS server under the jurisdiction of. cn;
5. If. if the cn server has the resolution information for this domain name, it will directly return the information to the local DNS server, and the local DNS server will then return the resolution information to the client; if. if the cn DNS server does not have the resolution information for this domain name, it will be governed. the DNS server of the cn DNS service informs .com.cn of the IP address of the DNS server;
6. The local DNS server requests the IP address of www.exmaple.com.cn from the DNS server under the jurisdiction of .com.cn;
7. If the .com.cn server has the resolution information for this domain name, the system will directly return the information to the local DNS server, and the local DNS server will then return the resolution information to the client; if the .com.cn DNS server does not have the resolution information for this domain name, the DNS server responsible for the .com.cn DNS service informs .example.com.cn of the IP address of the DNS server;
8. The local DNS server asks the DNS server under the jurisdiction of .example.com.cn for the IP address www. example.com.cn;
9. the DNS server under the jurisdiction of .example.com.cn informs www.exmaple.com.cn of the IP address of the DNS server;
10. The local DNS server resolves the IP address www.exmaple.com.cn and sends it back to the client.
Iv. Building a DNS server for RHEL 5
◆ System Platform: RedHat Enterprise Linux 5 update3
◆ Kernel version: 2.6.18-128. el5
◆ DNS Server IP Address: 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
I have described in detail how to build a DNS server for RHEL 5 from the above four aspects, and hope to help you.
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