|
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:
- Click Domains in your control panel home page.
- Select the domain if you have more than one.
- 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.
|
