What is DNS?
Domain Name System, or DNS for short, is the protocol that used translating readable URLs –
google.com or twitter.com – into the numeric addresses that can be understood by our computers.
How DNS Works?
- A web user enters a readable domain name of a website (like google.com) into the brower’s address bar.
- Then their device sends a DNS request to the ISP (Internet Service Provider) of the user.
- The ISP will determine if the domain name is associated with an valid IP address.
- When the IP address is located, the domain name is sent back to the device of the user.
- The device now can communicate with the server of the entered domain name, and the user can now view the website requested.
DNS Records Lookup Tools
DNS Lookup Tool that will find the IP address and perform a deep DNS lookup of any URL, providing in-depth details on common record types, like A, MX, NS, SOA, and TXT.
Most Common Types of DNS Records?
- A record – The record that holds the IP address of a domain.
- AAAA record – The record that contains the IPv6 address for a domain (as opposed to A records, which list the IPv4 address).
- CNAME record – Forwards one domain or subdomain to another domain, does NOT provide an IP address.
- MX record – Directs mail to an email server.
- TXT record – Lets an admin store text notes in the record. These records are often used for email security.
- NS record – Stores the name server for a DNS entry.
- SOA record – Stores admin information about a domain.
- SRV record – Specifies a port for specific services.
- PTR record – Provides a domain name in reverse-lookups.
Less Commonly Used DNS Records?
- AFSDB record – This record is used for clients of the Andrew File System (AFS) developed by Carnegie Melon. The AFSDB record functions to find other AFS cells.
- APL record – The ‘address prefix list’ is an experiment record that specifies lists of address ranges.
- CAA record – This is the ‘certification authority authorization’ record, it allows domain owners state which certificate authorities can issue certificates for that domain. If no CAA record exists, then anyone can issue a certificate for the domain. These records are also inherited by subdomains.
- DNSKEY record – The ‘DNS Key Record’ contains a public key used to verify Domain Name System Security Extension (DNSSEC) signatures.
- CDNSKEY record – This is a child copy of the DNSKEY record, meant to be transferred to a parent.
- CERT record – The ‘certificate record’ stores public key certificates.
- DCHID record – The ‘DHCP Identifier’ stores info for the Dynamic Host Configuration Protocol (DHCP), a standardized network protocol used on IP networks.
- DNAME record – The ‘delegation name’ record creates a domain alias, just like CNAME, but this alias will redirect all subdomains as well. For instance if the owner of ‘example.com’ bought the domain ‘website.net’ and gave it a DNAME record that points to ‘example.com’, then that pointer would also extend to ‘blog.website.net’ and any other subdomains.
- HIP record – This record uses ‘Host identity protocol’, a way to separate the roles of an IP address; this record is used most often in mobile computing.
- IPSECKEY record – The ‘IPSEC key’ record works with the Internet Protocol Security (IPSEC), an end-to-end security protocol framework and part of the Internet Protocol Suite (TCP/IP).
- LOC record – The ‘location’ record contains geographical information for a domain in the form of longitude and latitude coordinates.
- NAPTR record – The ‘name authority pointer’ record can be combined with an SRV record to dynamically create URI’s to point to based on a regular expression.
- NSEC record – The ‘next secure record’ is part of DNSSEC, and it’s used to prove that a requested DNS resource record does not exist.
- RRSIG record – The ‘resource record signature’ is a record to store digital signatures used to authenticate records in accordance with DNSSEC.
- RP record – This is the ‘responsible person’ record and it stores the email address of the person responsible for the domain.
- SSHFP record – This record stores the ‘SSH public key fingerprints’; SSH stands for Secure Shell and it’s a cryptographic networking protocol for secure communication over an unsecure network.