A Records
- What’s an A record?
- A record format
- Querying A records
- Manage A records
An A record maps a tên miền name vĩ đại the IP address (Version 4) of the computer hosting the tên miền. An A record uses a tên miền name vĩ đại find the IP address of a computer connected vĩ đại the internet
The A in A record stands for Address. Whenever you visit a trang web site, send an gmail, connect vĩ đại Twitter or Facebook, or tự almost anything on the Internet, the address you enter is a series of words connected with dots.
For example, vĩ đại access the DNSimple trang web you enter www.dnsimple.com. At our name server, there’s an A record that points vĩ đại the IP address 208.93.64.253. This means that a request from your browser vĩ đại www.dnsimple.com is directed vĩ đại the server with IP address 208.93.64.253.
A Records are the simplest type of DNS records, and one of the primary records used in DNS servers.
You can tự a lot with A records, including using multiple A records for the same tên miền in order vĩ đại provide redundancy and fallbacks. Additionally, multiple names could point vĩ đại the same address, in which case each would have its own A record pointing vĩ đại that same IP address.
The DNS A record is specified by RFC 1035.
A record format
The structure of an A record follows the standard top-level format definition defined in RFC 1035. The RDATA section is composed of one element:
| Element | Description |
|---|---|
| address | A 32 bit Internet address representing an IPv4 address |
Hosts that have multiple Internet addresses have multiple A records.
The canonical representation is:
A
where is an IPv4 address and looks lượt thích 162.159.24.4.
In DNSimple, the A record is represented by the following customizable elements:
| Element | Description |
|---|---|
| Name | The host name for the record, without the tên miền name. This is generally referred vĩ đại as “subdomain”. We automatically append the tên miền name. |
| TTL | The time-to-live in seconds. This is the amount of time the record is allowed vĩ đại be cached by a resolver. |
| Address | The IPv4 address the A record points vĩ đại. |
Querying A records
You can use dig vĩ đại determine the A record associated vĩ đại a tên miền name. The result is contained in the ANSWER section. It contains the fully-qualified tên miền name (FQDN), the remaining time-to-live (TTL), and the IP address.
$ dig A api.dnsimple.com
; <<>> DiG 9.8.3-P1 <<>> A api.dnsimple.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 5792
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;api.dnsimple.com. IN A
;; ANSWER SECTION:
api.dnsimple.com. 59 IN A 208.93.64.253
;; Query time: 80 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Sun Jul 31 22:21:31 2016
;; MSG SIZE rcvd: 50
Manage A records
From the DNSimple record editor, you can add, remove, and update A records.