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This document explains
What is DNS?
DNS can be considered something similar to a phone book.
When you move from one location to another, your name stays
the same, but your phone number may change. In order to
point your name to the new phone number, you must contact
the telephone service provider so they assign you the new
phone number and update all directory information to reflect
you as pointing to this new phone number.
In this way, the IP number can be compared to a phone
number: When someone calls http://www.example.com/, your ISP
looks at the DNS server, and asks "how do I contact
example.com?" The DNS server responds: "It can be found at
198.105.232.4". As the Internet understands it, this can be
considered the phone number for the server, which houses the
http://www.example.com web site.
The DNS records for your domain are kept on your hosting
server in the place called DNS zone. When you register a
domain by means of the control panel, all DNS records are
automatically created for you, but in some rare cases you
may need to add custom records to your DNS zone. An example
would be when you want all email to be processed by an
external mail server rather than by the built-in mail
system. However, such user intervention requires knowledge
of DNS configuration and clear understanding of what is to
be done.
How Do I Create Custom DNS records?
To create a custom record to your DNS zone, do the
following:
- Select Domain info in the Domain Settings
menu.
- On the page that appears, click the Edit icon in
the DNS Configuration field:
- This link will take you to the DNS Configuration
page:
On this page you can see several blocks of DNS records.
Some are built-in and non-removable; others are user-defined
and can be deleted. Built-in MX records require special
consideration: they can be removed by disabling mailservices
for this domain., but all e-mail resources, including
mailboxes, forwarders, and autoresponders will also be
deleted. The removal of H-Sphere 2.x email services was made
possible to enable the use of e-mail services provided by
other mail servers.
You can add any type of DNS records by clicking an
appropriate link. You will be asked to enter corresponding
DNS data.
Adding Custom A Records
Normally, A records are used to map domain names and web
server IP's.
If you have selected A record, the following page appears:
- Name: enter the string to map to the web server.
- TTL: set how many seconds will elapse before the
record is refreshed in the DNS cache.
- Data: enter the IP of the web server.
WARNING: Please pay attention to $ORIGIN when you add an A
record.
Adding Custom MX Records
Custom MX records should be added when you want to use your
external mail servers to process your e-mail. To use your
external servers instead of those you get by default,
you need to disable mail service on the Domain Settings
page of your control panel. To use the default mail servers
in addition to those you get by default, you need to
keep mail service enabled in the control panel. The priority
of the custom MX record will define whether your external
servers will act as secondary or primary. For instance, if
you set the priority of the custom MX record higher than 10
(e.g. 11), your external mail server will be used as
secondary. If you set the priority of the custom MX record
lower than 10 (e.g. 9), your external mail server will be
used as primary. In the latter case, your mail will be sent
to your external mail server until it goes down or becomes
otherwise inaccessible. Then the default mail server will
take over.
When you enable mail service in the control panel, an MX
record is created automatically in the DNS zone. If mail
service is disabled, this built-in MX record remains in the
DNS zone, and you can remove it manually using the control
panel interface.
If you have selected MX record, the following page appears:
- Name: your local domain name. If you leave the
Name field blank, all mail will be redirected for the
base zone.
- Data: the priority of the record and mail domain
name (not the IP) mail will be forwarded to.
IMPORTANT: To add an MX record for the base domain, leave
the Name field empty.
Adding Custom CNAME Records
Finally, CNAME records are used to map aliases with domain
names.
If you have selected CNAME record, the following page
appears:
- Name: The alias you give to the real host name.
- TTL: set how many seconds will elapse before the
record is refreshed in the DNS cache.
- Data: The real name of the host you create an
alias to. This must be an official host name. It cannot be
an alias. A CNAME-record should always point to an A-record
to avoid circular references.
WARNING: Please pay attention to $ORIGIN when you
add a CNAME record.
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