- DNS Servers are dedicated computers that look up the IP addresses associated with domain names. The DNS server stores a catalog of all the public IP addresses as well as domain names in use today.
- You can now find new uses for DNS mainly due to NS1 and other next-generation DNS services enabling advanced traffic routing capabilities.
- As part of DNS assault like cache poisoning, malefactors introduce false data into the DNS, usually by altering the cache.
You might already know that when you open up a web browser and type in a URL, your browser is requesting data from a web host server. However, the Domain Name System (DNS) also plays a part in the communication between your browser and the server. Protecting your privacy and speeding up your web browsing are just two of the many benefits of a Domain Name System (DNS).
In other words, DNS Servers are dedicated computers that look up the IP addresses associated with domain names like “example.com.” The DNS server stores a catalog of all the public IP addresses as well as domain names in use today.
An Internet Protocol (IP) address, in either the IPv4 or IPv6 format, is a unique identifier for each device on the internet. The same is true of servers that host websites on the Internet.
There are situations when many IP addresses can belong to a single domain name. For instance, huge websites such as Google have users from all over the world searching their servers.
Even if both the browser’s address bar and the server’s address bar have the same domain name, the server that a computer in Australia queries may not be the same as the server that a computer in Singapore actually reaches out to. When this occurs, DNS caching becomes useful.
Where Does DNS Come into Play?
When you go online and type a domain name into a browser, your computer takes the lead and resolves the hostname for you. Then, your machine consults its local DNS cache for the IP address corresponding to the domain name.
By the way, your computer keeps recently-saved data in this cache, so a webpage will load faster if it can be accessed from the local machine. If your machine does not already know the answer, it will issue a DNS query to find it.
It suggests that DNS be used for:
- Connecting databases, app servers, and middleware in applications,
- Resolving hostnames,
- Establishing virtual private networks,
- Routing messages to webmail services and email servers,
- Initiating peer-to-peer sharing programs,
- Communicating between gateways, IoT devices, and servers.
These are only some of the ways you can see DNS in action, but it has evolved considerably in the last two decades or so. You can now find new uses for DNS mainly due to NS1 and other next-generation DNS services enabling advanced traffic routing capabilities.
Some of these next-generation services include:
- Global Server Load Balancing – this enables fast routing of connections between data centers worldwide.
- Multi CDN – this involves sending users to the CDN for the best online experience.
- Geographical Routing – this involves the identification of a user’s physical location and then routing them to the nearest resource.
- Data Center and Cloud Migration – this helps manage traffic from on-premise resources to different cloud resources.
How Does a DNS Server Work?
A DNS server comes into action the moment you enter a domain name into your browser. Here are the steps involved in how it works.
1. Requesting Website Info
When you enter the domain name, the computer automatically resolves the hostname and looks for the IP address associated with it. Initially, it looks for it in its local DNS cache, but if it is unavailable locally, it initiates a DNS query to get that info.
2. Connecting with the Recursive DNS Server
A recursive name server is one that processes queries for the sake of providing further information. In contrast to traditional DNS servers, they do not maintain any records on their own.
The IP address is associated with an entry in the cache memory, accessed when a query is received. The query sender gets a response in case the recursive name server has any info.
The query automatically transfers to another recursive name server if it lacks the record. This keeps happening until the query gets to an authoritative DNS server that provides the IP address.
3. Querying the Authoritative DNS Server
When one or more recursive DNS servers cannot find the requested data in their cache, they will attempt to locate it in other ways. After that, the request is forwarded to the next higher-up in the DNS hierarchy.
As long as no nameserver for the domain is found, the search will continue. It is the job of these root name servers to keep these records for the domains they serve.
4. Accessing the DNS Record
The authoritative name server can retrieve a domain name’s address record (A record). One way that the “A record” can be retrieved from the authoritative name servers is by using a Recursive DNS server.
The data is thereafter cached locally. The recursive server would know the response if another query asked for the “A record” for that particular domain name.
A time-to-live value, or TTL, is included in all DNS records and indicates when a record will be deleted. Eventually, the recursive DNS server will request an updated copy of the records.
5. Finalizing the DNS Search
A machine can get the “A record” from a Recursive DNS server, which already holds the data. After that, the file is saved to your computer’s memory.
At the same time, the IP address is retrieved from the DNS record and forwarded to the browser. The IP address listed in the A records will direct the browser to the server hosting the requested website. The total time it takes to do a lookup is no longer than microseconds.
What Should You Know about DNS Difficulties?
Clearly, the Domain Name System is crucial to whatever actions you take on the internet. Therefore, your experience may deteriorate quickly if there are any issues with the system. So, what can go wrong here?
Inefficient DNS Server
To begin, your ISP‘s DNS servers can be a source of delay if they are inefficient or are not set up correctly for caching. This is especially the case when a page that incorporates content from numerous external sources is loaded.
When using the internet at home or at the office, switching to DNS servers designed for speed can significantly improve performance. How do you overcome the issue? Well, it is simple and all you have to do is go for companies that offer high-quality DNS services, probably with business-friendly add-ons.
The added benefit is that they can block access to sites that are known to be harmful. They do so at the DNS level, preventing them from being loaded in an employee’s browser. In this way, it is possible to block potentially offensive websites.
Similarly, parents can take advantage of DNS-based parental control systems to restrict their children’s access to mature or otherwise unsuitable information across all devices.
Local DNS Issue
In order to speed up responses to frequently used queries, your DNS server stores them in a cache and retrieves them without consulting other DNS nodes. Your computer also maintains a local DNS cache, which might cause problems when it becomes corrupted. There is no need to change DNS servers to fix this issue. Simply clearing your local DNS cache will do the trick.
Remember that your ISP’s DNS servers know about every domain name you’ve requested; unless you’re using a VPN. In most cases, it does not matter, and your ISP does not even care. But sometimes, some service providers use it to their advantage.
For instance, if you type in a domain that does not exist, your browser will be redirected to a search and advertising page with a query generated from the domain name.
Again, this might not appear to be a problem at first glance, but it could have serious implications for your personal privacy. What started out as a safe exchange of information between your browser and the DNS server is now at risk.
This occurs because your Internet service provider (ISP) diverts a copy of your request to an incorrect destination. So, you should not take it lightly, or it might lead to serious consequences, including the DNS ending up under attack.
What Are DNS Attacks?
You have probably heard about phishing before. Criminal webmasters create a site that seems much like a legitimate one, such as PayPal, a gaming site, a bank, or a dating service. Using spam, fraudulent advertisements, or other methods, they spread links to the phony site.
If an unsuspecting user goes in without realizing it is a phony, they have just handed the bad guys access to their account. The fraudsters then use those credentials to log you into the legitimate site, where you remain unaware of the attack.
The address bar is the one and only giveaway for many scams. To avoid becoming a victim of phishing, it helps to keep a close check on the address bar. Sometimes, it is easy to spot the forgery, like a site that falsely presents itself as LinkedIn, but actually uses a completely unrelated domain name (like ABC.com).
Some go to greater lengths to trick you by using slightly different names like Paypel.com or incredibly long URLs to hide their true domain. But a savvy internet user will see through any deception.
Speaking of DNS attacks, cache poisoning is among the most troublesome. As part of this type of assault, malefactors introduce false data into the DNS, usually by altering the cache.
When a user enters a legitimate domain name, the address bar displays the IP address for a fake site, since the DNS system has been poisoned. There would be no outward sign of sabotage; unless the criminals perform a particularly bad job of spoofing the intended site.
Local DNS hijacking is also common and usually targets your machine. When malware is active, it modifies the system’s TCP/IP configurations to point to a malicious DNS server.
Obviously, this is only effective if the malware in question is able to bypass your antivirus software, but some people still have not gotten the memo about installing antivirus software on all of their computers.
A DNS server is a testament to the fact that today’s internet architecture has evolved significantly. These days, we have moved to a client/server network model in which clients start connections and servers react.
This is in part because the IPv4 address pool has run dry but also because of an architectural evolution that is needed to deal with the tremendous expansion in the number of devices in networks.
Things are surely getting better and more sophisticated in the DNS realm, but it is essential to understand that DNS is attractive for everybody – and we mean everybody! Those who make their living off the Internet are naturally quite curious about what people do on it.
Criminal behavior on the Internet is of essential concern to those agencies whose job is to police such behaviors because every crime is a cybercrime nowadays.
So, the DNS is always under attack. But, thankfully, new and improved security software solutions are becoming available to offer some peace of mind. The sooner your business realizes that DNS security is crucial, the better.
It becomes especially critical as you and your workforce become more reliant on remote access. You should think about making it a central part of your company’s network security solution once you have familiarized yourself with what it implies and how it will influence you.
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