DNS records are basically mapping files that tell the DNS server which IP address each domain is associated with, and how to handle requests sent to each domain. When someone visits a web site, a request is sent to the DNS server and then forwarded to the web server provided by a web hosting company, which contain the data contained on the site.
DNS database is collection of resource records and each of the records provides information about specific object, A list of most comman records is provided below:
- Address Mapping records (A): The record A is the most basic type of syntax used in DNS records, indicating the actual IP address of the domain.
- IP Version 6 Address records (AAAA): The record AAAA (also quad-A record) specifies IPv6 address for given host. So it works the same way as the A record and the difference is the type of IP address.
- Canonical Name records (CNAME): The CNAME record specifies a domain name that has to be queried in order to resolve the original DNS query. Therefore CNAME records are used for creating aliases of domain names. CNAME records are truly useful when we want to alias our domain to an external domain. In other cases we can remove CNAME records and replace them with A records and even decrease performance overhead.
- Mail exchanger record (MX): The MX resource record specifies a mail exchange server for a DNS domain name. The information is used by Simple Mail Transfer Protocol (SMTP) to route emails to proper hosts. Typically, there are more than one mail exchange server for a DNS domain and each of them have set priority.
- Reverse-lookup Pointer records (PTR): As opposed to forward DNS resolution (A and AAAA DNS records), the PTR record is used to look up domain names based on an IP address.
- Name Server records (NS): The “NS” record indicates which Name Server is authoritative for the domain.
- Start of Authority records (SOA): The record specifies core 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.
- Service record (SRV): The SRV record is used to define a TCP service on which the domain operates.
- Text records (TXT): The text record can hold arbitrary non-formatted text string. Typically, the record is used by Sender Policy Framework (SPF) to prevent fake emails to appear to be sent by you.
DNS database is collection of resource records and each of the records provides information about specific object, A list of most comman records is provided below:
- Address Mapping records (A): The record A is the most basic type of syntax used in DNS records, indicating the actual IP address of the domain.
- IP Version 6 Address records (AAAA): The record AAAA (also quad-A record) specifies IPv6 address for given host. So it works the same way as the A record and the difference is the type of IP address.
- Canonical Name records (CNAME): The CNAME record specifies a domain name that has to be queried in order to resolve the original DNS query. Therefore CNAME records are used for creating aliases of domain names. CNAME records are truly useful when we want to alias our domain to an external domain. In other cases we can remove CNAME records and replace them with A records and even decrease performance overhead.
- Mail exchanger record (MX): The MX resource record specifies a mail exchange server for a DNS domain name. The information is used by Simple Mail Transfer Protocol (SMTP) to route emails to proper hosts. Typically, there are more than one mail exchange server for a DNS domain and each of them have set priority.
- Reverse-lookup Pointer records (PTR): As opposed to forward DNS resolution (A and AAAA DNS records), the PTR record is used to look up domain names based on an IP address.
- Name Server records (NS): The “NS” record indicates which Name Server is authoritative for the domain.
- Start of Authority records (SOA): The record specifies core 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.
- Service record (SRV): The SRV record is used to define a TCP service on which the domain operates.
- Text records (TXT): The text record can hold arbitrary non-formatted text string. Typically, the record is used by Sender Policy Framework (SPF) to prevent fake emails to appear to be sent by you.
