A DNS record is a domain name system record that helps users visit a website without having to memorize its IP address. It basically translates easy-to-remember domain names to their corresponding IP addresses and presents the desired web results.
An IP address is a long string of numbers separated by dots, which makes them harder to remember; hence, a domain name system was put in place. Moreover, an IP address linked to a domain name can change if there are any alterations on the server hosting the website.
So, let’s explore different DNS record types and their purposes.
Types of DNS Records
DNS records are text-based, which allows DNS administrators to edit and adjust them quickly and easily. Each DNS record performs a different function and works in alignment with various technologies to fulfill desired purposes like email security, domain management, identifying authoritative name servers, creating alias domain names, etc.
Officially, there are around 90 unique DNS record types, each of them demanding a proper configuration and management in order to avoid a drowned website performance. The following are the commonly used DNS record types:
A Record
It’s one of the most utilized DNS record types, and A in the A record stands for ‘address.’ While performing an IP address lookup, an A record retrieves the corresponding IPv4 IP address to a domain name.
This means if you request your browser to navigate you to DuoCircle’s website, then the A record responsible for the lookup tasks would find the IP address linked to DuoCircle’s website. An A record’s capabilities aren’t restricted to this. It also blocks emails coming from known spam sources by cross-checking with the domain name system-based blackhole list (DNSBL).
Please note that using multiple A records for the same domain causes redundancies and triggers issues.
AAAA Record
AAAA record, often called a quad-A record, works almost like an A record. The only difference is that it directs towards an IPv6 address, which is the upgraded version of IPv4.
An IPv6 address is alphanumeric and separated by colons. Just as A records, multiple AAAA records are troublesome too.
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DNS PTR Record
PTR is short for the Pointer Record, one of the common DNS record types whose function is completely the opposite of that of an A record. It’s used for reverse DNS lookup, which means when you enter an IP address and expect the search results to return with the corresponding domain name. PTR records contain IPv4 addresses with segments in reverse order and IPv6 address segments in the reversed order of hexadecimal digits.
It generally behaves as an anti-spam tool. This is because a recipient’s mail server uses the DNS PTR record in the message to verify if the sender’s email server corresponds to the IP address it claims. This minimizes the likelihood of email spoofing and phishing attacks, which could otherwise trick email receivers into sharing sensitive information and documents or clicking malicious links.
MX Record
An MX record or mail exchange record contains a list of domain names of mail servers responsible for accepting emails on behalf of a domain. It helps sort out authorized mail servers and is often tagged as an MX entry, specifically when involved in email servers’ configurations.
Mail providers with multiple servers have to assign a priority value to instruct the DNS in which sequence they should contact the servers. The email server assigned the lowest value has the highest priority and serves as the initial point of contact. Servers with higher values come into play only if the primary ones are unavailable.
Nevertheless, the DNS evenly distributes the workload among email servers having the same priority. Similar to NS records, MX records cannot direct to a CNAME record or a domain alias.
CNAME Record
A CNAME or canonical name record is a DNS record type that directs users to an alias domain (a subdomain or different domain) to the primary domain name. For example, a CNAME record can direct the web address www.duocircle.au to the primary website, that is, www.duocircle.com, so as to show that both domains belong to the same company. This ensures you get the most out of the web traffic and your users don’t get lost on the web.
It’s recommended to use a canonical name record if your website has multiple subdomains. Also, you don’t have to make any edits to the CNAME record if any changes are made to your IP address, as all of them point to the same main domain. Record administrators have to make changes to the A or AAAA records only.
You need to keep the following points in mind while using a CNAME record-
- Never place a canonical name record in the root domain.
- It should always direct to another domain name and not an IP address.
- Avoid pointing a CNAME record to another CNAME record.
- Never point a CNAME record to NS and MX records.
- There shouldn’t be any other resource record with the same name besides DNSSEC records, such as NSEC and RRSIG.
NS Record
An NS record is short for a name server record, a DNS record type that indicates the authoritative DNS server and specifies which DNS server contains all the actual zone files or DNS records of a specific domain.
Usually, NS records let the internet know which specific nameserver or DNS server includes the IP address of the queried domain. Your website won’t load in the absence of a properly configured NS record.
SOA Record
SOA record stands for Start of Authority record. It contains important details about your DNS zone or domain and monitors traffic between primary and secondary nameservers.
It helps in zone transfers, which is basically the process where DNS records are shared between nameservers. A DNS file zone is invalid in its absence.
An SOA record has the following set of additional information-
- MNAME – Primary nameserver of the domain or zone.
- RNAME – Nameserver administrator’s email address.
- REFRESH – DNS zone file refresh interval.
- SERIAL – Nameserver’s or zone’s serial number.
- RETRY – Refresh retry interval.
- EXPIRE – No response timeout.
TXT Record
A textual or TXT record is a frequently encountered DNS record type that holds human-readable, explanatory data. It is typically combined with other DNS records to supply supplementary details.
A single domain can encompass numerous TXT records. These TXT records find applications in services related to Domain-based Message Authentication, Reporting, and Conformance (DMARC), Sender Policy Framework (SPF), and DomainKeys Identified Email (DKIM). In essence, a TXT record can be employed for validating domain ownership and mitigating spam.