DNS Lookup

   CNAME Lookup
   MX Lookup
   NS Lookup
   SPF Lookup
   TXT Lookup

The Domain Name System (DNS) is an important protocol part of the web's infrastructure, serving as the Internet's phone book. This protocol is implemented by multiple DNS servers located all over the world.

A DNS Server is a server which translates and resolves human-memorable domain names (example.com) into the corresponding numeric Internet Protocol (IP) addresses (93.184.216.34). More technically, a DNS Server stores a lot of information about a given domain name known as DNS Records and responds with answers to queries against its database.

A DNS Record is a piece of information about a domain name , such as:

• A Record (IPv4 address)
• AAAA Record (IPv6 Address)
• NS Record (Name Server)
• MX Record (Mail Exchanger)
• TXT Record (Text Data)

A DNS Lookup / DNS Check / NameServer Lookup / NSLookup is the process of querying one or multiple Domain Name System (DNS) servers, and obtain all DNS records for a given domain name. This operation is also known as Forward DNS Lookup.

• A DNS Lookup is used to find out a given domain DNS records, in order to troubleshoot DNS related problems
• A DNS Lookup is also necessary to check the propagation of recently changed DNS records accross Worldwide public DNS servers

• Open the Online DNS Lookup Tool
• Enter a domain in the space provided
• Click on the "DNS Records Lookup" button

The Online DNS Lookup Tool will then search and find all domain DNS records available in the selected DNS Servers and gives you the result.

To perform a DNS Lookup, you must use the linux NSLOOKUP command-line utility:
For a Domain DNS records Lookup: nslookup [domain] (Ex: nslookup google.com)
To get a Domain all available DNS records: nslookup -type=any [domain] (Ex: nslookup -type=any google.com)
Lookup for an A record (IPv4 Address): nslookup -type=a [domain]
Lookup for an AAAA record (IPv6 Address): nslookup -type=aaaa [domain]
Lookup for a NS record (Name Server): nslookup -type=ns [domain]
Lookup for a MX record (Mail Exchange): nslookup -type=mx [domain]
Lookup for a SOA record (Start of authority): nslookup -type=soa [domain]
Lookup for a TXT record (TXT record): nslookup -type=txt [domain]

To perform a DNS Lookup, you must use the command nslookup
The nslookup command queries the DNS servers in two modes: Interactive mode and noninteractive mode.
For a Domain DNS records Lookup: nslookup [domain] (Ex: nslookup google.com)

A DNS Checker is another name used to mean a DNS Lookup Tool

Type	Description	Function
A	IPv4 Address record	Returns a 32-bit IPv4 address, most commonly used to map hostnames to an IP address of the host, but it is also used for DNSBLs, storing subnet masks in RFC 1101, etc.
AAAA	IPv6 address record	Returns a 128-bit IPv6 address, most commonly used to map hostnames to an IP address of the host.
AFSDB	AFS database record	Location of database servers of an AFS cell. This record is commonly used by AFS clients to contact AFS cells outside their local domain. A subtype of this record is used by the obsolete DCE/DFS file system.
CAA	Certification Authority Authorization	DNS Certification Authority Authorization, constraining acceptable CAs for a host/domain
CERT	Certificate record	Stores PKIX, SPKI, PGP, etc.
CNAME	Canonical name record	Alias of one name to another: the DNS lookup will continue by retrying the lookup with the new name.
DHCID	DHCP identifier	Used in conjunction with the FQDN option to DHCP
DNAME	Delegation name record	Alias for a name and all its subnames, unlike CNAME, which is an alias for only the exact name. Like a CNAME record, the DNS lookup will continue by retrying the lookup with the new name.
DNSKEY	DNS Key record	The key record used in DNSSEC. Uses the same format as the KEY record.
DS	Delegation signer	The record used to identify the DNSSEC signing key of a delegated zone
IPSECKEY	IPsec Key	Key record that can be used with IPsec
LOC	Location record	Specifies a geographical location associated with a domain name
MX	Mail exchange record	Maps a domain name to a list of message transfer agents for that domain
NAPTR	Naming Authority Pointer	Allows regular-expression-based rewriting of domain names which can then be used as URIs, further domain names to lookups, etc.
NS	Name server record	Delegates a DNS zone to use the given authoritative name servers
NSEC	Next Secure record	Part of DNSSEC—used to prove a name does not exist. Uses the same format as the (obsolete) NXT record.
NSEC3	Next Secure record version 3	An extension to DNSSEC that allows proof of nonexistence for a name without permitting zonewalking
NSEC3PARAM	NSEC3 parameters	Parameter record for use with NSEC3
PTR	PTR Resource Record	Pointer to a canonical name. Unlike a CNAME, DNS processing stops and just the name is returned. The most common use is for implementing reverse DNS lookups, but other uses include such things as DNS-SD.
RP	Responsible Person	Information about the responsible person(s) for the domain. Usually an email address with the @ replaced by a .
RRSIG	DNSSEC signature	Signature for a DNSSEC-secured record set. Uses the same format as the SIG record.
SOA	Start of [a zone of] authority record	Specifies authoritative information about a DNS zone, including the primary name server, the email of the domain administrator, the domain serial number, and several timers relating to refreshing the zone.
SRV	Service locator	Generalized service location record, used for newer protocols instead of creating protocol-specific records such as MX.
SSHFP	SSH Public Key Fingerprint	Resource record for publishing SSH public host key fingerprints in the DNS System, in order to aid in verifying the authenticity of the host. RFC 6594 defines ECC SSH keys and SHA-256 hashes. See the IANA SSHFP RR parameters registry for details.
TLSA	TLSA certificate association	A record for DANE. RFC 6698 defines "The TLSA DNS resource record is used to associate a TLS server certificate or public key with the domain name where the record is found, thus forming a 'TLSA certificate association'".
TSIG	Transaction Signature	Can be used to authenticate dynamic updates as coming from an approved client, or to authenticate responses as coming from an approved recursive name server[13] similar to DNSSEC.
TXT	Text record	Originally for arbitrary human-readable text in a DNS record. Since the early 1990s, however, this record more often carries machine-readable data, such as specified by RFC 1464, opportunistic encryption, Sender Policy Framework, DKIM, DMARC, DNS-SD, etc.
URI	Uniform Resource Identifier	Can be used for publishing mappings from hostnames to URIs.