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Home > Monitoring Toolbox > Monitor DNS responses witht his tool
April 21, 2022
For most of us, the inner working of the internet remains a black box. You might not strictly recall seeing a DNS error, but it probably has popped up on your screen at one point or another leaving you to wonder what it means. Similarly, behind the scenes, the DNS lookup process plays an integral role in simplifying how users find DNS records.
What is a DNS Lookup?, Types of DNS Servers, how a DNS query works?, Types of DNS Records,
Here, we detail how DNS Lookups work and the crucial records/metrics to keep in mind. If the information of this tools gets you confused, take a look at the FAQ section below, to get to know what each of these entries mean
DNS stands for Domain Name System. It is a system that translates the human-readable domain name you type in your browser to the machine-readable IP address at which the requested web page is placed.
Too much jargon? Let’s simplify things. The Domain Name is a name you give to your site, for example, “fun.com.” Think of it as the name of a famous building, says Buckingham Palace.
The IP address is the address of the server where your website is placed. This corresponds to the building address you’re trying to get to. For example, “London SW1A 1AA, United Kingdom.”
Now your browser is your cab driver. When you ask your browser to take you to “fun.com,” it looks for the IP address using DNS, much like your cab driver would look for the address to Buckingham Palace on their navigation app.
In short, DNS is the navigation app that helps your browser to convert the name of a website into its IP address and take you there.
Now that we understand what DNS is let’s briefly look at the DNS servers’ types: DNS Recursor, Root Nameserver, TLD Nameserver, Authoritative Nameserver
The DNS Recursor is the first stop for the query your browser generates when looking for a webpage. As the name suggests, the function of the Recursor is recursive. It keeps sending out requests to different nameservers until it finally finds the specific IP address your browser needs.
As is in the name, the Root Nameserver is the server that holds the index of all the addresses active on the internet. This is the first server where the Recursor sends the query. It looks for the right Top Level Domain Name and sends that back to the Recursor.
The Top Level Domain (TLD) is the part of the website’s name that comes after the dot, like “.com,” “.tech,” etc. Each of these has its own TLD Nameserver. This is the server the Recursor contacts to know which Authoritative Nameserver has the IP address for the requested site.
The Authoritative Nameserver is run by the authority who hosts or maintains the site, hence the name. This can be the domain registrar or the site’s host. This is the last server the Recursor contacts, which tells it the exact IP address of the site it’s looking for.
DNA A Record, AAAA Records, CNAME Records, MX Records, TXT Records, NS Records, SOA Records
As we have seen, a site’s DNS information is vital in ensuring that your browser can find and retrieve the information it contains. But websites aren’t as simple as just a single webpage.
Today’s websites can have many functions like email services, malware blocking, and even subdomains. So several types of records are required to house vital information for the DNS servers to be able to fetch and display the website with its complete functionality.
Let’s look at the essential types of DNS records:
The ‘A’ Record or Address Record contains the primary IP address (in IPv4 format). It is where your entire website, including subdomains, etc., is hosted. The IP contained in this record is the first address referenced in a DNS lookup and points to the website’s root.
The “AAAA” Record is just a longer “A” Record. The four A’s indicate that it can support a longer length. This record houses the IP address for your site, just like the “A” Record. Still, it does so in the longer IPv6 format, which conforms to the new IPv6 protocol and allows for more unique addresses.
The “CNAME” or “Canonical Name” Record stores an old name for your website and is used when pointing one domain to another. For example, if you wanted “amusement.co” to redirect automatically to “fun.com,” you’d put “fun.com” in its CNAME.
“Mail Exchange” or “MX” is the record that holds the server’s name through which the email for your website needs to be routed. This tells the DNS where to send requests for sending, receiving, and viewing emails for email addresses on your website’s domain.
A “TXT” or “Text” record is what it says on the tin. It allows you to add any text to your website’s DNS information. This record is sometimes used by third parties like email service providers to confirm you own the site by telling you to add a specific string to your TXT record.
“NameServer” or “NS” Records hold the server’s address that houses your site’s DNS information. These servers are what we called Authoritative Nameservers earlier when discussing types of DNS. This information tells your site’s TLD Server to ask for the rest of the site’s DNS information.
The “Start Of Authority” or “SOA” Record holds information about the site’s administrator, including email, contact information, and the address to the primary nameserver. This gives the browser and DNS servers helpful information about the site’s administrator for troubleshooting.
What are NS Checks?, What are SOA Records?, What are MX Checks?, What are MX Reverse entries?, What is an MX DNS Blacklist, What Is Email Validation?, What is an Email Authentication (DMARC)?
Other than what we’ve already covered, a few things are often confusing when learning about DNS. Here are the answers to some common queries on the subject.
NameServer checks ensure that a site’s NameServers are active and that the DNS can resolve the site’s name in every region. Looking up the NS Records for a site can help ensure it is up, is pointed to the correct NameServers, and is not malicious.
As discussed already, SOA contains meta-information about the site’s administrator. SOA checks can help ensure that the correct information is available in the DNS lookup and the website’s legitimacy.
Mail Exchange or MX Checks help ensure the Mail Servers are correctly configured. They also help to ascertain whether the particular MX Server is legitimate and whether the site can be trusted to send and receive emails.
MX Reverse Entries are entries in the Mail Servers’ Pointer (PTR) Record that allows Reverse DNS lookup. This means that a server can find the Mail Server’s name through its IP addresses instead of the other way around.
MX DNS Blacklists are records containing the IP addresses of Mail Exchange Servers known to be sending out spam emails. These play a crucial role in helping prevent spam and malicious emails from reaching your domain’s email accounts.
Sender Policy Framework or SPF is an authentication protocol for email that creates a list of authorized IP addresses permitted to send emails from the domain in its DNS TXT record. The receiving server can check this and determine whether an email is genuine or spam based on the sender’s IP.
DMARC is a protocol for authenticating emails and preventing phishing and spoofing. It allows the domain owner to specify what to do with emails that cannot be authenticated to have come from a legitimate sender. The DMARC DNS Record sets the policy to ignore, quarantine, or bounce incoming messages.
Now you know the basics of a DNS lookup, how it works, and the associated metrics/records. We hope it has helped you better understand the World Wide Web (WWW).
