What is the Difference Between Master and Slave DNS Server

The main difference between master and slave DNS server is that the master DNS server reads data related to the domain zone and communicates with the slave DNS server while the slave DNS server is a server that obtains zone data from the master DNS server immediately after being set up.

DNS is a server that converts the domain names to corresponding IP addresses. DNS server can be a master or slave DNS. The server administrator can configure a DNS to be master or slave. A DNS zone is a container of DNS setting and records of a DNS namespace. Moreover, it is also possible for a single sever to work as a master and a slave server. It can work as master server in a zone while working as a slave server in another zone.

Key Areas Covered

1. What is Master DNS Server
     – Definition, Functionality
2. What is Slave DNS Server
     – Definition, Functionality
3. What is the Difference Between Master and Slave DNS Server
     – Comparison of Key Differences

Key Terms

DNS Server, Domain Name, IP Address, Master DNS Server, Primary DNS Server, Secondary DNS Server, Slave DNS Server

What is Master DNS Server

Master DNS server is also known as the primary DNS server. It reads data related to the domain zone. It also communicates with the slave servers. The server administrator instructs the servers on how to communicate with other web servers. A master server communicating with the slave server is called a zone transfer.

Figure 01: DNS Server

Every domain name in the network is assigned to DNS servers for redundancy. This process simplifies the server administration task. If a primary server already contains the zone data for a domain, it is not necessary to replicate this data. This is because the master and slave DNS continuously share zone data. When there is a request to a server, it first travels through the master slave. Then the master slave will allocate functionalities to the slave server.

What is a Slave DNS Server

A secondary DNS server is also called the slave server. After it is configured, it receives zone data from the master server. Every time the slave DNS server works, it obtains data from the master DNS server. Slave DNS servers are also important as the master servers. This is because they offer security through redundancy. Furthermore, the slave servers minimize the request load on the master DNS server.

Difference Between Master and Slave DNS Server

Definition

Master DNS server is a server that stores the original copies of all zone records. In contrast, slave DNS server is a server that uses a special automatic updating mechanism to communicate with the master server to maintain an identical copy of data similar to the master server. These two definitions explain the basic difference between master and slave DNS server.

Synonyms

Master DNS server is called the primary DNS server while Slave DNS server is called the secondary DNS server.

Number of DNS Servers

Each zone can only have a single master DNS server, but it can have multiple slave DNS servers. This is another difference between master and slave DNS server.

Data

Moreover, an important difference between master and slave DNS server is that the master server gets information directly from the local files. On the other hand, slave server contains read only copies of the zone file, and it gets data by communicating with the master server.

Usage

Aboveall, the main difference between master and slave DNS server is that the master DNS server hosts the controlling zone file, which contains all the authoritative information for a domain. However, slave DNS server provides redundancy when the master slave goes down. It also reduces the request load on the master DNS server.

Conclusion

In summary, a DNS server can serve as a master or slave DNS. The main difference between master and slave DNS server is that the master DNS server reads data related to the domain zone and communicates with the slave DNS server while the slave DNS server is a server that obtains zone data from the master DNS server immediately after being set up.

Reference:

1. “Domain Name System.” Wikipedia, Wikimedia Foundation, 3 Oct. 2018, Available here.

Image Courtesy:

1. “Dns-server” By Б.Өлзийдэлгэр – Own work (CC BY-SA 4.0) via Commons Wikimedia