DNS Records Entries (Examples Please)


I currently have the ability to edit the following records in my DNS control panel from my hosting provider who provides me with web and email hosting. I have looked in the internet at what these mean but I am still not too sure on what they can be used for and was really looking for some real life examples of what they are used for and when I might want to update them and any more information about them that might be useful. I would really like to learn about these more.

The records I have the ability to change are :

A Record (Address Record)
CNAME Records (Canonical Name Record)
MX Record (Mail Exchange Record)
AAAA Record (IPv6 Address Record)
SRV Record (Service Locator Record)
SPF Record (Sender Policy Record)
TXT Record (Text Record)

If examples could be given for what each are used for and when you might want to change them that would be a great start.


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-A Record (Address Record) points to domains and hostnames with defining a static IP address of a choice, the most coommon record.  http://www.ntchosting.com/dns/host.html

-MX record identifies the server to which e-mail is directed

-CNAME record is used to create aliases that point to other names, usually A records

-AAAA records similar to the A record, but it allows you to point the domain to an Ipv6 address

-SPF record -when a mail server receives an email it can check the DNS zone of the sending domain for a SPF record.,t hat will tell them if the email did indeed come from that domain name, using an authorised SPF address. This stops spammers forging mail headers, i.e. pretending that their email came from your domain when it didn’t.

-TXT record  (text) - is used to hold some text information. You can put virtually any free text you want within a TXT record. A TXT record has a hostname so that you can assign the free text to a particular hostname/zone.

- SRV record -is an advanced type of record which allows you to specify services that you have on your domain.
For example, you might want to specify that you have FTP access on your domain. You could use a CNAME to create a subdomain, but this would only tell people the address of the server. An SRV record will tell people the following information in addition to the address:

The Service Name (e.g. _ftp)
The Protocol (e.g. _tcp)
The Port Number that this service is on (e.g. 21)
The Priority (An arbitrary number which tells people which record to pick if you have several SRV records with the same Name and Protocol)
The Weight (Another arbitrary number which tells people which records should be used more often if you have several SRV records with the same Name and Protocol

Hope this helps

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Miguel Angel Perez MuñozCommented:
A record is used on inverse resolution. Resolves IP into a hostname.
CNAME record is an "alias". When you create a cname, resolver uses them to get original name and after, resolves the name. Example, I create an alias server.yahoo.com for www.yahoo.com. When I try to resolve server.yahoo.com, client get www.yahoo.com. Then, resolve www.yahoo.com.
MX record is used to publish email servers for this domain. Yo can have various with different priority (lower number is first priority).
AAAA is equal to A record but used for IP v.6
SRV Record is used to publish a service.
SPF Record is used to publish email servers authorized to send email on one domain. Is used to fight against spam.
TXT record is a record that have text on his response.
gisvpnAuthor Commented:
Hi aladin404 & Drashiel.

Thanks for the posts. Could i ask a few questions.

Regarding the SPF Record It sounds like this is some sort of validation system to reduce or prevent SPAM being used by the domain I own? Do you have any examples of what I might want to configure/set up or change here. Currently the domain has no records attached to the SPF record. I can however configure a hostname and value - but I am not sure on what these are.

I am not sure I understand the TXT record; what would it actually be used for, do you have an example at all of when this would be used.

Many thanks, this has helped!



A Record (Address Record) - If it was not for A record we would have been typing IP Addresses to browse various websites on the internet. To put it simply, each A record has two entries: HostName e.g. experts-exchange.com and an IP Address mapped to it such as So, now when you browse to experts-exchange.com your browser looks up a Name Server and finds out that it needs to talk to for retrieving content.

CNAME Records (Canonical Name Record) - Canonical Names are primarily Aliases to A records created earlier. Now question Why to create a CNAME Record when I can create a A record and they both serve the same purpose. The logical reasoning behind this is, how about having 10 A records for one IP Addresses and you had to suddenly change the IP Address, this would mean you have to update 10 A records, but if you were using CNAME you would have update only one A record.

MX Record (Mail Exchange Record) - These records are kinda transparent to us but are used primarily for Mailing Servers to find the SMTP server for your email address. Now, you may have your webmail running on different server and SMTP on different server. Simply put MX records generally have the SMTP Server address.

AAAA Record (IPv6 Address Record) We are still waiting for full IPv6 adoption, soon these will play the role A records have been playing for a while.

SRV Record (Service Locator Record) A Service record (SRV record) is a specification of data in the Domain Name System defining the location, i.e. the hostname and port number, of servers for specified services. Some Internet protocols such as the Session Initiation Protocol (SIP) and the Extensible Messaging and Presence Protocol (XMPP) often require SRV support by network elements. If you had ever used Domain Logon, it runs on the basis of SRV records such as
_ldap._tcp.reskit.com SRV 0 0 389 phoenix.reskit.com

SPF Record (Sender Policy Record) Sender Policy Framework (SPF) is an email validation system designed to prevent email spam by detecting email spoofing, a common vulnerability, by verifying sender IP addresses. SPF allows administrators to specify which hosts are allowed to send mail from a given domain by creating a specific SPF record (or TXT record) in the Domain Name System (DNS). Mail exchangers use the DNS to check that mail from a given domain is being sent by a host sanctioned by that domain's administrators. Read more on SPF @ http://www.zytrax.com/books/dns/ch9/spf.html

TXT Record (Text Record) A TXT (text) record is used to hold some text information. You can put virtually any free text you want within a TXT record. A TXT record has a hostname so that you can assign the free text to a particular hostname/zone. The most common use for TXT records is to store SPF (sender policy framework) records and to prevent emails being faked to appear to have been sent from you.

Hope this helps....

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