What is a DNS Lookup?

DNS Lookup is a process or internet protocol used to translate a domain into an IP address and vice versa. When we talk about DNS lookup then by it we mean 2 opposite techniques. The first is forward lookup and the second is reverse lookup.

Forward & Reverse DNS

With forward lookup, we look for the IP address that corresponds to a specific domain. In reverse lookup, as opposed to forward lookup, we search for the domain or host name that corresponds to the given IP address via the IP address self.
Reverse DNS lookup for IPv4 addresses uses the in-addr.arpa domain. So for example reverse lookup for IPv4 address 9.9.9.9 will be 9.9.9.9.in-addr.arpa

When we talk about IPv6 addresses then they unlike IPv4 addresses use a special domain ip6.arpa. In this case, the IPv6 address 2620: 1ec: c11 :: 200 in reverse resolution will be 0.0.2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.1.c.0.c. e.1.0.0.2.6.2.ip6.arpa

Check DNS Records

DNS lookup is primarily designed to check DNS records for domains. So here you can get information about the following DNS record types:

  • A record - details about 32-bit IPv4 associated with the domain
  • AAAA record - details regarding the 128-bit IPv6 used by the host
  • MX record - A mail exchanger used by the domain to send email
  • NS record - Authoritative NS - name servers
  • SOA record - specifies authoritative information including email from the administrator of the requested domain, serial number of the domain and a couple of other indicators
  • TXT - text record

Check out DNS records for well-known domains with the most traffic such as Wikipedia, Youtube, Facebook, Amazon or Google.

For isolated specific tests for NS and MX where you can get extra information about the priority of mail servers and their IP addresses do not forget to check NS Lookup and especially MX Lookup.

  • IP Details
  • IP: 34.200.252.156
  • Hostname: ec2-34-200-252-156.compute-1.amazonaws.com
  • DNS
  • Reverse DNS
  • 156.252.200.34.in-addr.arpa
  • NS - The Authoritative Nameservers: [ Class: - TTL: ]
  • r1.amazonaws.com (205.251.192.27)

    u2.amazonaws.com (156.154.65.10)

    u1.amazonaws.com (156.154.64.10)

    r2.amazonaws.com (205.251.195.199)

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