What is DNS, DNS Monitoring Tools, How does DNS work, DNS Attacks, DNS Monitoring, Why use DNS Monitoring? What is DNS? The Domain Name System is a service that - simply stated - resolves human-friendly domain names into a computer-understandable IP address. This IP address enables the browser to find the server. The combination of host name and IP address forms the so-called namespace. A DNS is a hierarchical distributed database, each containing a piece of information leading to a particular web page or device on the network. The system uses TCP and UDP for transmission and is probably one of the busiest databases in the world. What are the best DNS monitoring tools? Paessler PRTG, Solarwinds, Nagios, DotCom, ManageEngine, UpTrends, DNSCheck, 24x7 When it comes to monitoring, there are a few components to keep track of. This is where effective DNS server monitoring software comes into play. These tools provide detailed insights that are usually not possible and protect DNS servers from attacks and inform when performance is poor. Here is an overview of the best DNS monitoring tools available: Paessler PRTG Paessler PRTG is one of the best and most popular network monitoring tools and can also be used as a powerful DNS monitor. It specializes in DNS server availability and performance and provides information in an intuitive and attractive way. The dashboards are clean and clear, and the graphs, scales and charts are colorful and easy to read, making data interpretation faster and more accurate. PRTG includes DNS sensors and DNS monitoring is an automated process that runs behind the scenes, checking the availability and performance of DNS servers. It not only monitors your DNS servers in real time, but also records all measurement data. This gives you the possibility to always retrieve detailed statistics about your DNS servers. SolarWinds Server & Application Monitor SolarWinds Server & Application Monitor (SAM) is built to monitor DNS server performance and help head off issues that could affect end-user experience. SAM can be used as a DNS user experience monitor to help Admins check DNS server ability and ensure the server responds to a record query within an acceptable threshold. SolarWinds SAM is designed to compare query response time against a list of IP addresses to help ensure DNS is performing at an acceptable baseline. SAM is also built to support DNS server management for different types of servers. Nagios XI DNS monitoring is part of Nagios XI and Nagios Core tools, both renowned monitoring tools used by many users and organizations. Nagios allows to monitor DNS servers, protocols and queries; achieve increased availability of servers, services and applications; quickly detect network failures and protocol errors; and quickly detect DNS hijacking and spoofing. The Nagios monitoring solution can be extended with third-party components listed in Nagios Exchange, such as wizards and plugins. The tool was created with fast-paced environments in mind, meaning any DNS issues in your network should be detected within seconds or minutes. So, if you are keen to use an open source, highly complex software, Nagios can be what you are looking for. Dotcom-Monitor Dotcom-Monitor provides a simple DNS monitoring tool. It evaluates the request times, responds with a DNS trace and sends a warning if there are problems. If any issues are detected with resolving DNS names, an instant DNS trace is taken that shows the full path of propagation, as well as an instant alert, showing the type of issue and extent of the error. Performance reports are generated showing global resolution speeds. One of the advantages of this monitoring tool is that it supports a variety of records, ranging from AAAA to NS, CNAME, TXT, SPF, and many others. This helps quite a bit with troubleshooting, as you gather much more information than you otherwise would. ManageEngine Applications Manager Applications Manager offers comprehensive DNS monitoring with real-time alerts to make sure your DNS server performance is always maximum and no issues that can impact the performance of your business applications go unnoticed. It helps to make sure critical services are up and running at all times, ensure constant connectivity of websites and servers, and quickly identify DNS issues. With detailed monitoring, intelligent alerts and reports to analyze performance trends, Applications Manager could be a good solution for anyone looking for a DNS monitoring tool. UpTrends UpTrends is a free DNS lookup tool for monitoring DNS health 24/7 and offers generous functionalities. UpTrends lets you monitor all the important DNS records, including A, AAAA, SOA, TXT and MX. Additionally, root servers can be monitored so that you know when DNS has been interfered with. This allows DNS poisoning to be stopped before it affects server health and performance. UpTrends also tracks SOA serial numbers to ensure that no changes have gone unnoticed. Furthermore, DNS servers can be checked worldwide. A regional problem can spread to the rest of the DNS network, and UpTrends is good at detecting and resolving these problems before they spread. DNS Check Although limited, an easy to use DNS monitor DNS Check is another simple tool. It monitors any differences or search errors for name servers and DNS records. However, it is by no means a comprehensive tool. If one values alerting and event response utilities, DNS Check must be combined with other products. However, it is a tool that should be considered for monitoring DNS. DNS Check can automatically set up scans to identify incorrect IP addresses, missing DNS records, duplicate DNS records, remote IP addresses, unresponsive name servers, out-of-sync name servers, and more. One advantage of DNS Check is that you can choose whether to import the entire zone or individual records to be monitored. It is also a great tool for collaboration, since links can be shared that show which records have been properly published and which have not. Site24x7 DNS Server Monitoring Site 24/7 Monitoring dashboard Site24x7 offers a multi-tool for DNS monitoring that alerts operators as soon as an error or misconfiguration occurs. It can check websites from over 90 locations around the globe. The tool not only checks whether a website is visible, but also investigates the reason for the outage, if there is one. Site24x7 performs continuous DNS checks and issues an alert whenever a DNS error occurs that prevents the end user from reaching a website. The alert system ensures that there is no need to constantly look at a dashboard to find problems. Instead, technicians can perform other tasks and take care of the DNS only after the problems have occurred. Download the Full Version for 30 days How does DNS work? The “resolving process” refers to the conversion of domain names to IP addresses. Users have no insight into that resolution process, which takes place in the background. When the hostname is entered into a browser's search bar, there is a moment - typically less than a second - when the request is resolved. Although this procedure takes only a few microseconds, there are four different types of DNS servers involved: the DNS-Recursor (also known as recursive DNS server)the root name serverthe TLD (Top Level Domain) name serverthe authoritative name server Each of them has a different purpose, and they work together to provide access to users to the content they request. What threats are DNS servers exposed to? In a DNS attack, an attacker exploits vulnerabilities in the DNS. Even though the DNS system is fairly robust, it was designed primarily for steady operation, not for the highest level of security. That is why there are many different ways to attack the DNS system today. A lot of these attacks are very complex and take advantage of the communication between the clients and the servers. Another attack technique is to log in to a DNS provider's website with stolen credentials and redirect DNS records. Typical types of DNS attacks: Zero-Day-Exploit: Attackers are targeting previously unknown vulnerabilities in the DNS protocol or in the DNS software used.Cache Poisoning: In this case, attackers manipulate the DNS system by replacing an IP address in the server's cache with another address. This allows attackers to redirect web surfers to fake websites, collect data, or perform other types of attacks. It is also known as DNS poisoning.Denial of Service (DoS): a bot sends out more traffic to a specific IP address than it can handle in its data buffers. The destination can then no longer respond to legitimate requests.Distributed Denial of Service (DDoS): Compared to DoS, an attacker here uses a botnet to send a large number of requests to a target address in a short period of time.DNS Amplification: Since too many server requests cannot be responded to, they are forwarded to other servers. Attackers can use this method to spread their attacks far and wide or to amplify them. What is DNS monitoring and how does it work? During a DNS monitoring process, automated queries are sent to a desired DNS server and the results are validated for a specific domain name. One of the most common methods is to query the DNS server with a URL and verify the IP address returned in the A record or AAAA record. The appropriate response to these queries is the correct IP address, which corresponds to the URL being used. If the correct IP address is received, no further action is required, and monitoring continues. However, if a different IP address is returned, the monitoring tool starts a so-called DNS incident and starts notifying. A DNS incident is a period when a Domain Name System is unavailable or returns incorrect records. However, it can also mean that the request sent by the monitoring tool does not receive a response within a defined period of time. Why using monitoring DNS monitoring is important? To ensure the accessibility of your own website, monitoring the DNS record is very important. If there are DNS problems - of whatever kind - customers can no longer reach the online store, for example, which can quickly have a financial impact on a company. Monitoring DNS increases both the reliability and security of this service and is very powerful in detecting some common hacking attacks such as a DDoS attack or DNS poisoning. The advantages are obvious: DNS monitoring can run 24/7. It is fully automated and requires little to no maintenance once set up, while still providing the same valuable information.DNS monitoring can be set up in a very short time, while availability information is provided from the beginning.DNS monitoring enables testing of different endpoints around the globe. This enables differentiation of regional faults from incidents that affect all users.