Difference Between DNS and DHCP (With Table)

DNS and DHCP are two systems that are made up of client-server architecture. They are essential services in the IT network that are accessed every time a network-connected device is used. Their purpose is to make the use of networks or the internet easier. Both of them work differently with hosts and IP addresses.


The difference between DNS and DHCP is that DNS, which stands for Domain Name System is a mechanism that allows users to translate their domain names to IP addresses and vice versa. On the other hand, DHCP, which stands for Dynamic Host Configuration Protocol, is a mechanism that helps users configure hosts mechanically.

DNS mechanism provides the users with a directory lookup service. This facility maps the name of the host as well as its IP address. The mapping is carried out using a host file. These files are saved on every host and are modified regularly based on a master host file. Whenever a user needs to map a domain name to an IP address and vice versa, the host file is consulted.

DHCP is an arrangement that allots dynamic IP addresses to all the hosts that are connected to a network. These addresses are leased for a particular time span which can be extended on request. The system includes the combination of a protocol with a mechanism. Both have a specific function of their own.

Comparison Table Between DNS and DHCP

Parameters of ComparisonDNSDHCP
Full-FormThe full form of DNS is Domain Name System.The full form of DHCP is Dynamic Host Configuration Protocol.
FunctionIts function is to translate domain names to IP addresses and vice versa.Its function is to allot IP addresses to every new host connected to the network.
SystemThe system of DNS is decentralized.The system of DHCP is centralized.
Supported ProtocolIt supports both UDP and TCP protocols.It only supports UDP protocol.
PortIt works on only one port which is port no. 53.It works on two ports which are port no. 67 and 68.

What is DNS?

DNS is a naming system for hosts. It is hierarchal and decentralized in nature. The function of the mechanism is to translate readily memorized domain names into numerical IP addresses. These make it easy for locating and identifying different hosts that are connected to the network. Moreover, the system also associates various information with the domain names of the hosts.

The system removes the hassle of a single large central database. It does so by providing distributed and fault-tolerant services. DNS essentially delegates the duty of giving domain names and mapping them to internet resources. This is done by creating authoritative name servers for each domain.

The DNS also specifies the technical functionality of the central database service. It comprises of an Internet Protocol Suite. This suite defines the DNS protocol and gives a comprehensive specification list of data structures as well as data communication exchanges that take place in the system.

There are various records that are stored in a DNS mechanism. These include Start of Authority, IP addresses, name servers, domain name aliases, SMTP mail exchangers, and pointers for reverse DNS lookups. Over time, the system has been expanded to store more records for automatic lookups and even human queries.

What is DHCP?

DHCP is a network management protocol that is used on IP networks. Its function is to allocate an IP address and other communication parameters to every host that enters the network. This is done using a client-server architecture. An advantage of using DHCP is that it eliminates the need for configuring network devices manually. Unlike DNS, the system is fully centralized.

The system includes two components which are a centrally installed network server and client protocols. On connecting to a network, the client requests a set of parameters from the server. This is done using the protocol included in the system.

The protocol system can be used on all networks, be it small or large. They work on regional IP networks, large campus networks and even small residential networks. Several routers these days also use this kind of protocol. The DHCP service exists for networks that run on IPv4 and IPv6 as well.

The first DHCP system was defined in RFC 903 in 1984. Then, it was called the Reverse Address Resolution Protocol. It was used for the configuration of simple devices. However, implementation was made difficult on various server platforms as the system acted as a data link layer.

Main Differences Between DNS and DHCP

  1. DNS stands for Domain Name System whereas DHCP stands for Dynamic Host Configuration Protocol.
  2. The function of DNS is to translate domain names to IP addresses and vice versa whereas that of DHCP is to allot IP addresses to every new host connected to the network.
  3. The system of DNS is decentralized whereas that of DHCP is centralized.
  4. DNS supports UDP and TCP protocols whereas DHCP only supports UDP protocols.
  5. DNS only works on port no. 53 whereas DHCP works on port no. 67 as well as port no. 68.


DNS and DHCP are very essential services on IT networks. Understanding the difference between them can be quite confusing due to all the jargon involved. However, a simple distinguishing feature is that they both have very different functions. DNS translates domain names to IP addresses and vice versa whereas DHCP allots addresses dynamically to every new host that enters the network.

Apart from this, both have several other features that are clearly different. For example, DNS has a decentralized system whereas DHCP has a centralized one. Moreover, DNS can work on only one port whereas DHCP can work on two ports. Regardless, both the systems have several overlapping characteristics as well.

Understanding their similarities and differences can play a crucial role while troubleshooting. They can also help a user to know the mechanics of how systems work with domain names and IP addresses.


  1. https://link.springer.com/content/pdf/10.1007/978-0-387-74390-5_5.pdf
  2. https://www.researchgate.net/profile/Sameena-Naaz-3/publication/316877345_Investigating_DHCP_and_DNS_Protocols_Using_Wireshark/links/59155c8eaca27200fe4eb5d7/Investigating-DHCP-and-DNS-Protocols-Using-Wireshark.pdf
2D vs 3D