| Resource Record |
Friendly Name |
Description |
| A |
Host Address |
An A record is the most basic DNS resource record. It points a domain name to
an IP address. A records can only point to IP addresses. |
| AAAA |
IPv6 Address |
An AAAA record is the same as an A record, but for IPv6 IP addresses. |
| CNAME |
Alias |
A CNAME is an Alias, or canonical name. It points clients to another record for an
answer. A typical CNAME entry might include the "www." prefix for a
webserver. Alias records are not required for the proper workings of the
Internet. One can easily setup their DNS without using a single CNAME
record. CNAME records cannot point to IP addresses. |
| MX |
Mail Exchange |
An MX resource is used to define the incoming SMTP server for a domain. It is
used by mail servers to know where to deliver email for a particular domain. |
| NS |
Nameserver |
Nameserver records define the authoritative nameservers for a domain. Since it
is not necessary for each domain to run its own nameservers, NS records are
used to point clients to the nameservers for the domain. An NS record
must be defined for each authoritative nameserver of a domain. |
| SOA |
Start of Authority |
An SOA record is defines the caching characteristics for a particular domain.
There is only one SOA record for a domain name (although it can be re-defined
in sub-domains). SOA records also define how secondaries behave when
their primary DNS server is down, as well as how often to refresh DNS
records. Many of the parameters to an SOA record are now rather obsolete
as notifications from the primary DNS server are often more a more effective
means of communicating changes.
|
| SRV |
Service Record |
SRV records are used to find services available on the domain. It contains the
priority, weight, port and hostname for a particular service. |
| TXT |
Text |
Text records are a mechanism for extending the DNS system without having to
create a new resource-record type. A rather new and novel approach to
fighting unsolicited email called Sender Policy Framework (SPF) uses TXT
records to determine whether a domain has authoritzed a sender to send email on
its behalf.
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