How to prevent DNS downtime?

Everybody wants to avoid DNS downtime! Unfortunately, it affects your reputation, annoys your loyal and potential clients, and costs you money.

DNS downtime is the time your domain name won’t be resolved to its corresponding IP address. During that time, clients won’t be able to use your service or load your domain. An error will be pointed out every time they request it.

The Domain Name System (DNS) is the keystone for the Internet to work. No matter its dimension and importance, it also suffers from vulnerabilities, hacking attempts, software and hardware issues, networks’ problems, database corruption, etc. And if it stops, your domain also will.

How can you prevent DNS downtime?

To know that prevention is possible, it’s always good news, especially when your investment is at risk!

  • Set up a higher TTL (time-to-live) on your DNS records. Recursive servers’ job involves looking for updates on authoritative name servers. If you configure a high TTL value, recursive servers will look for updates less often. But with a low TTL value, they will look for updates more frequently. A low TTL is really convenient when you modify or edit DNS records because it accelerates the propagation process. If you don’t need constant changes, keep a higher TTL to avoid downtime. If your authoritative name server fails, a high TTL increases the chances for a copy of your DNS records to remain longer in the cache of a recursive. Thus your domain will still be loaded for clients, and you get more time for fixing the problem.
  • Use Secondary DNS servers. Increase redundancy while adding Secondary servers to your DNS network. More copies of your DNS records will be stored through this action, and you will manage your traffic more efficiently. No matter if your Primary DNS server gets suddenly in trouble, the Secondary ones will answer your clients’ requests.
  • Monitor the DNS server exhaustively. Every uncommon traffic pattern can mean something important. Get a proficient monitoring tool. Some can show you almost in real-time the information, by region, country, continent, etc., for you to diagnose the problem, its origin, and react.
  • Enable DNS Failover. This is an ideal teammate for monitoring, and due to its flexibility, it can be configured with the most convenient parameters for your business. Data obtained from monitoring can be connected to the DNS Failover. If a DNS nameserver fails, DNS Failover will automatically redirect the traffic from the server facing the issue to a healthy one. DNS resolution will continue working, despite your server’s problems.
  • Use DNS load balancing. This is a useful mechanism for distributing traffic across servers. For working, it considers factors such as the number of active connections, connection time, etc. By having two or more servers, DNS load balancing will manage traffic, for servers to have kind of the same amount of work, not to be sluggish or very stressed. It’s an efficient way to manage traffic spikes that can be normal or a symptom of malicious activity in progress. It directly boosts performance, prevents security issues and downtime. If a server fails or gets compromised, another will answer your clients’ requests. 
  • Strength your defenses against DDoS attacks. These threats involve enormous amounts of traffic overwhelming your system. Anti-DDoS technology protects your servers to resist such traffic.

Conclusion

You can prevent DNS downtime! There are easy or more complex alternatives. Your business’ needs will define the right one or the appropriate combination of them. Decide it today, and keep your business always up!

Recursive DNS server: What does it mean?

The Recursive DNS server is one of the main elements in the Domain Name System (DNS). Let’s explain a little bit more about it.

Recursive DNS server explained.

The Recursive DNS server is responsible for searching for required information. The goal is to respond to the queries which are sent by users. Recursion in computing is associating with a method to resolve an issue. It involves a solution or a program that will continue to repeat itself till it reaches its goal. 

Picture it like that. It is operating between the authoritative servers and the end-users. 

Every time someone makes a request for a domain name, this DNS server searches for its IP address. When the it receives the accurate IP address, it returns it to the device or browser that initiated the request. The device takes the data, and it connects to the specific IP address. And the domain finally can load.

Performing the lookup

There are two different ways for the recursive DNS server to perform its lookup.

The first one is definitely easier and faster. It is to receive the information from the cache. These type of servers store their cache for a determined period of time. The administrators make the decision of how long the server should hold the data. Through the time-to-live (TTL) value, they are able to set more or less time. And that decision is usually based on their strategy.

So, when the recursive DNS server obtains a query, it can check first its cache memory. If the IP address for the particular domain name, which is requested, is still stored. The TTL of the cache should not be expired yet, and the data to be available. In this case, the response is faster because the recursive DNS server doesn’t need to search in other servers.

The second way of performing a lookup takes a little longer time. It happens when the cache TTL is expired. The IP address is not held there anymore, and the recursive DNS server takes the long path. It has to search for an authoritative server, which is capable of giving the required information.

So, the main purpose of this DNS server is just to look for information, and it saves it for some time. 

Recursive DNS server in DNS cache poisoning attacks

When a recursive DNS server searches for an IP address from another DNS server, the attacker stops the request. Instead of the real information, the attacker will give a fake answer. This answer usually is an IP address for a malicious website. And like that, the DNS cache poisoning attack is successful.

The problem is not only that the recursive server gave the user this fake IP address. Moreover, the server will store the answer on its cache. This fact leads to a huge problem. Every user who wants to access the same domain will receive the fake IP address, and it will connect with the malicious site. Imagine a case when that domain is very popular. Such an attack is going to affect a lot of visitors.