What is DNS and its components
The Domain Name System (DNS) is the system which performs an extremely important function. The primary task of DNS is to allocate names to different IP Addresses. It cannot be neglected that human find it easy to remember names rather than numerical IP Addresses. In order to provide facility to the humans, the DNS system stores a relational database of names and IP Addresses and establishes links between them. This ensures that each of the IP Address on the network is given a particular name which is easily accessible. The existence of this system makes sure that every server on a TCP/IP-based network can be accessed easily by just typing the name of the server. However, if this service fails to respond then all of us will literally have to remember the IP Address of each server separately in order to access. Hence, this shows how much integral is a DNS system in a network.
There are various components of DNS that enable it to function properly and also provides it with certain additional facilities. Below, you will find the detail of components which are related with DNS.
The DNS servers enable the whole process of resolution of names with IP Addresses to take place. This means that DNS servers play in integral role in allocating names to IP Addresses and the resolving them on client's request. When you connect to the internet, you use the DNS servers every time in order to access the correct IP Address associated with the URL which you types. There are generally two ways in which the addresses of DNS servers could be accessed by a computer or a client. In the first case, one can connect to the internet using as ISP, Internet Service Provider. This internet service provider is responsible for providing you all the addresses on the DNS servers which you will use to resolve the URL or the website with its IP address. However, if you are using an IP network, you have the right to configure the client manually with all the addresses of DNS servers which they are supposed to use. This shows the flexibility in this process and exhibits the amount of relaxation one has while configuring these DNS servers.
It is important to note that there are loads of DNS servers over the internet. It might be possible that you are not able to find the associates IP Address with your URL on one DNS server. This is the reason why your request is forwarded to other DNS servers that maintain a relational database of names and IP addresses. This forwarding of requests make sure that the client is able to find the required IP Address in order to access the server which it is willing to. There are some special DNS servers which are known as Forwarders. These types of DNS servers facilitate the clients by processing Recursive queries. These forwarders make sure that they figure out the URL for the requested name and then provide it back to the client. However, in case it is not able to perform this task, it forwards all of its queries to other DNS servers until it gets back the perfect result. This process in which the requests are forwarded to other servers is known as Referral. All of the DNS servers are not able to perform this special task. The basic concept used behind this process is of iterative query, which makes sure that the request is forwarded to other servers until the desired result is acquired.
DNS servers also perform a process known as Reverse name lookup. This enables the servers to find out the name related to a corresponding IP Address. This means that the server will be provided with the IP Address and it will search its database to find its corresponding name. This is possible because of the existence of a relational database which makes sure that the information can be searched by either providing the name or the IP Address. In addition to this, there are some DNS servers which do not host the DNS namespace but are only developed for the purpose of resolving names with IP Addresses. These special kinds of DNS servers are known as Caching-only servers.
By this, we can conclude that there are thousands of DNS servers available which primarily perform the task of resolving IP Addresses with their respective names. However, they are also able to perform a number of other tasks which provide them with a better approach towards their work and enable them provide the client with the exact match for the information requested. These thousands of DNS servers work together to make sure that they are able to resolve every IP Address with its respective name.
Although we have talked about the DNS servers, but the sole prerequisite that makes these servers function are the DNS records. DNS records are essentially the database records in which all the information regarding the IP addresses and their corresponding names is stores. Whenever a computer or a client joins a network, its related information is stored in a Resource Record. These records might be created manually or maintained automatically by DNS servers. There are a number of ways in which these records could be stored and accessed by the servers. Following are the most essential resource records which are utilized by DNS servers.
A: This resource record stores the addresses in a 32-bit format. It comprises of a relational database of names and their respective IP addresses. It is basically associated with providing the addresses for an IPv4 network. It is one of the most widely used resource records. The primary purpose of A is to deal with the requests from the servers and convert the names into IP addresses to provide the IP address back to the server.
MX: MX is also known as Mail Exchanger. It is responsible for storing the information regarding the directing of emails on the server. It help figure out that at which location is a particular mail supposed to be delivered. Whenever a DNS server has to send or forward a mail to a particular address, it looks the MX record to serve its purpose.
AAAA: AAAA is a resource record which stores the addresses in a 128-bit format. It comprises of a relational database of names and their respective IP addresses. It is basically associated with providing the addresses for an IPv6 network. It is not as widely used on the internet web server as "A" because the internet generally works on IPv4. The primary purpose of AAAA is to deal with the requests from the servers and convert the names into IP addresses to provide the IP address back to the server.
CNAME: CNAME is also known as Canonical Name. It provides the facility to have more than one name associated with a client or a computer's IP Address on a network. This means that it holds more than one name records for the IP Addresses on a network. This secondary name will be available in the DNS database. CNAME record works in conformation to the A or AAAA records.
PTR: PTR is also referred to as Pointer. It is used primarily to facilitate the task of reverse name lookups. It provides with the names of the clients which are associated with a particular IP Address. It can be thought to function in the opposite way as an A or AAAA record does.
It is important to note that the standard procedure for DNS records on the internet is "A" as the internet works on IPv4. Furthermore, in order to facilitate the users, you have the facility to create more than one name for a particular IP address. This can either be done by using CNAMEs as discussed above or by using multiple records for names in an A or AAAA record. These varieties of records which are available to the DNS servers allow them to function in many special circumstances. The process of DNS holds an essential requirement to have well-maintained records in order to allow the servers to carry out their task perfectly. In addition to this, these records make it quite easy for the servers to look for the required information as they all maintain a relational database. This is the reason why the process of DNS works with a great deal of perfection.
Dynamic DNSIf you are working with a small network where the IP addresses are assigned manually to each computer on the system, you might not have to face any problem. However, in reality, the networks are quite large and complex. Before knowing about Dynamic DNS, one needs to be familiar with the process of DHCP. DHCP is the process is which IP Addresses are automatically assigned to computers which join a network. This is quite essential to make sure that every client on the network has a different IP address with which it can access the network. However, the main problem arises when the devices are provided with different, automatically generated IP Addresses whenever they join the network. The continuous changing of IP Addresses makes the overall concept of DNS void. In order to get out of this issue, the concept of Dynamic DNS has been introduced.
Dynamic DNS is referred to the automatic messages which are generated by a DHCP or any related servers when they change the IP Address of a device. This message is sent to the DNS servers which enable the record of the IP Address of that device to be updated to the new one. This is a continuous process which ensures that each computer or device on a network has the latest information regarding its IP Address stored on the DNS server records. This process is quite crucial make sure that you are able to find the exact IP address of the client or server which you are looking for in order to access it.
One more advantage of a DNS server is related to accessing the desktops of computers remotely. It is important to realize that those computers which are in a DHCP environment have to face the continuous changing of their IP Addresses on a regular basis. This means that the existence of these dynamically changing IP Addresses limits you from accessing the computer remotely. In order to facilitate you in this regard, the DHCP server again sends the message regarding the updated record to the DNS servers. Using this dynamic DNS, the servers are able to update their information and allow you to again access your computer remotely with ease. In fact, the introduction of Dynamic DNS has catered to a lot of related problems and has provided an amazing solution to these issues.
The system of DNS is widely used and cannot afford any problems or limitations due to the growing of networks. This concept of dynamically updated IP Addresses poses a big problem to the DNS system which would have remained inefficient without the existence of Dynamic DNS. It has not only provided a remedy to this problem, it has made the process of the maintenance of DNS records better and more specialized.
We have dealt in detail with the extensive process of Domain Name System. It is interesting to note that there are a number of factors which contribute to the success of this great system. It is not easy to maintain an updated version of such a system and make sure that every request is entertained in the best possible way. The mechanisms which are used in this technique are undoubtedly amazing. The perfect collaboration of the DNS servers with the DNS records makes sure that the best output is generated and the solutions to various requests are provided in the minimal time. In fact, the various facilities provided by the DNS records including the assigning of multiple names to a single IP address are what make this system more flexible and advantageous. It is not wrong to term DNS as one of the most integral and perfect systems in the process of networking.