DNS Lookup setup guide

Every time you type a website’s name into your browser, your device does a DNS lookup. It finds the correct IP address.

DNS (Domain Name System) lookup helps in translating a human-friendly domain name into a numerical IP address. After that, Computers use it to locate servers.

If there is no DNS lookup, you’d have to remember long strings of numbers instead of website names.

A fast and accurate DNS lookup is important for smooth Internet browsing and website performance. If DNS resolution is slow, websites take longer to load, and if it fails, the site won’t load at all.

How DNS Lookup Works?

When you enter a domain name, your device starts a step-by-step process to find the IP address. 

First, it checks its local cache to see if the IP is already stored. If it’s not, it asks for a recursive DNS resolver, which usually comes from your internet service provider (ISP).

The resolver queries authoritative DNS servers, which store official records for domains. The query moves up the hierarchy from a root DNS server to a top-level domain (TLD) server. They finally come to the domain’s authoritative nameserver. 

The IP address gets back to your device, and the website loads. To speed things up, DNS records are cached at various levels. It helps you to reduce lookup time for future visits.

Example A Records:

example.com.  3600  IN  A  192.168.1.1 Maps the domain example.com to the IPv4 address 192.168.1.1.

Example of AAAA Record:

example.com.  3600  IN  AAAA  2001:db8::1

Maps the domain example.com to the IPv6 address 2001:db8::1.

Example of CNAME Record:

www.example.com.  3600  IN  CNAME  example.com.

Example of MX Record:

example.com.  3600  IN  MX  10 mail.example.com.

How Domain Names Are Resolved Into IP Addresses?

When you’re studying DNS lookups, it also requires you to know terms that define how domain names are resolved into IP addresses. Here are some of the most important terms:

1. DNS (Domain Name System): A global system that translates human-readable domain names (like example.com) into numerical IP addresses.

2. DNS Resolver: A server that processes DNS queries from users and retrieves the IP address from DNS servers.

3. Recursive Lookup: A DNS query where the resolver contacts multiple DNS servers to find the requested IP address and returns a final answer to the user.

4. Non-Recursive Lookup: A query where the resolver already has the cached DNS response and can provide an instant answer without further requests.

5. Authoritative DNS Server: The server that holds the official DNS records for a domain and provides accurate and final answers to DNS queries.

6. Root Name Server: The highest level in the DNS hierarchy that directs queries to the correct top-level domain (TLD) name servers.

7. TLD Name Server: A DNS server that manages domain extensions like .com, .net, and .org and directs queries to the appropriate authoritative DNS server.

8. A Record (Address Record):  A type of DNS record that maps a domain name to an IPv4 address.

9. AAAA Record (Quad A Record): Similar to an A record but maps a domain name to an IPv6 address.

10. CNAME Record (Canonical Name Record): An alias record that redirects one domain to another.

11. MX Record (Mail Exchange Record):  A DNS record that specifies the mail server responsible for handling email for a domain.

12. PTR Record (Pointer Record): It’s used in reverse DNS lookup and maps an IP address back to a domain name.

13. SOA Record (Start of Authority Record): It has administrative details about a domain, such as the primary DNS server and update intervals.

14. TTL (Time to Live): The duration a DNS record is stored in the cache before it expires and needs to be refreshed.

15. DNS Cache: A temporary storage that keeps DNS query results to speed up future lookups.

Types of DNS Lookups

DNS lookups come in different forms, each has a specific purpose:

• Forward DNS Lookup: This is the most common type, where a domain name is converted into an IP address. This is what happens when you visit a website.

• Reverse DNS Lookup: It’s the opposite of a forward lookup. The system finds the associated domain name if the IP address is given. This is often used in email verification and security checks.

• Recursive Lookup: When a DNS resolver takes full responsibility for resolving a query. It moves through multiple servers until it finds the correct answer.

• Non-Recursive Lookup: It works as a quicker lookup where the resolver already has the requested record cached and doesn’t need to contact other DNS servers.

DNS Lookup Performance and Optimization

Even a fast-performing website can appear slow if DNS lookups are delayed. Every additional millisecond counts, especially for your business. To improve performance, you can:

• Use a fast and reliable DNS provider 

• Reduce unnecessary redirects that increase DNS queries.

• Optimize caching settings to store DNS records longer.

• Enable DNS prefetching, where browsers pre-load DNS resolutions for linked domains.

Why Do You Need DNS Lookup?

DNS lookup has multiple advantages that enhance your internet functionality, security, and efficiency. 

One of its primary benefits is user convenience. It allows people to access websites using easy-to-remember domain names instead of complex numerical IP addresses.

This also ensures scalability and helps websites to change hosting providers or IP addresses without disrupting user access.

Moreover, DNS caching improves speed when it stores previously resolved queries. This reduces the time needed to load frequently visited sites. 

From a security point of view, DNS filtering and security protocols help block malicious websites and prevent phishing attacks and malware distribution. 

Businesses rely on DNS load balancing to distribute traffic across multiple servers. It helps with faster website performance and high availability.

What Are Common DNS Lookup Errors?

DNS issues can cause your website to become inaccessible. Some common errors include:

• DNS_PROBE_FINISHED_NXDOMAIN: This means the domain name doesn’t exist or DNS settings are misconfigured. Fixing it may require verifying domain registration and checking DNS records.

• SERVFAIL: A server failure response, usually due to misconfigurations or DNS provider issues. Switching to a different resolver can help.

• Timeout Errors: If DNS queries take too long, users may see connection timeouts. This can be caused by slow resolvers or network issues. Flushing the DNS cache or switching to a faster DNS provider can resolve the issue.

FAQs

What is the difference between forward and reverse DNS lookups? A forward lookup translates a domain name into an IP address, while a reverse lookup finds the domain name associated with an IP address.

Can DNS lookups affect my website’s SEO? Yes. Slow DNS resolution times can increase page load times, negatively impacting SEO rankings.

How often should I clear my DNS cache? When you clear your DNS cache, it helps you resolve connectivity issues and ensures you have the latest DNS records. 

What happens if my DNS lookup fails? Your browser won’t be able to find the website, resulting in an error message. Troubleshooting involves checking your internet connection, switching DNS providers, or verifying DNS settings.

Conclusion

DNS lookup is an essential process that allows users to access websites without memorizing complex IP addresses. A fast and reliable DNS provider ensures smooth browsing and better website speed. By managing DNS settings correctly, you can enhance security, avoid downtime, and keep your online presence running seamlessly.