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DNS
Settings
This
section contains essential information about making DNS changes to your
web site. Please read this document thoroughly. Topics
include an important message for beginners, a short DNS tutorial, an explanation (with examples) of: A, CNAME,
NS, and MX records, and how to
change DNS settings.
Important
Message for Beginners 
The
ability to change the DNS configuration of a web site is an important
feature for many people. However, incorrect DNS modifications can
take an entire web site down for an extended period of time. This
is because DNS changes aren't instant (see the Tutorial below). If
you make a mistake, it is possible that nobody will be able to connect
to your site (including yourself). If you fix the mistake, it may
take up to 72 hours for the repair to take effect.
There
are several things you can do to prevent mistakes:
1.
Read this document thoroughly.
2.
Make sure you understand what A, CNAME, NS, and MX records do.
3.
Contact your web host for additional help and guidance.
4.
Don't make a major change without assistance.
With
a little bit of practice, you will find that making DNS changes is very
simple.
DNS
Tutorial
DNS
(Domain Name Servers) tell computers how to find each other over
Internet. When you type an address in your browser, your ISP
(Internet Service Provider) checks with it's domain name server (DNS) to
determine where to send you.
http://www.domain.com
---> Check with DNS ---> DNS says domain.com = 192.168.0.1
---> You are taken to web site.
Why
does this happen?
It
happens because your domain name won't always have the same IP
address. Each server on the Internet has an IP address (a
numerical address like a phone number). Every time you change web
hosts, you are changing servers (and therefore changing IP addresses).
Domain
name servers keep a record of your domain name and what IP address
(server) it should point to.
Why
must I put my web host's name servers (DNS) in my domain record?
As
you learned above, name servers tell the Internet how to find you.
When you edit the name servers in your domain record, you are telling
the Internet which name server provides the most up-to-date
directions. If you don't change the name servers in your domain
record (let's say you use your old web host's DNS), then your web site
will point to a server that isn't hosting your domain. Or, if the
old web host deleted you from their DNS, your domain wouldn't work at
all.
Why
does it take so long for my site to start working?
When
you change web hosts (addresses) or register a domain for the first
time, the new DNS information has to reach every other name server (DNS)
on the Internet. Your site may work in as few as 4 hours, but the
average waiting time is 24-72 hours. This delay occurs because
most name servers (DNS) choose to periodically check for updates.
That is, they aren't "live." Periodic checking is done
because constant checking often slows down the server.
Why
is my domain pointing to my old host, even though I cancelled my account
with them?
There
could be several reasons for this:
1.
Their name servers are still in your domain record.
Solution: Update your domain record with your new web host's name
servers (DNS).
2.
They haven't removed your domain record from their name servers.
Solution: Ask them to remove your domain record, or follow the solution
in #1 if you have a new web host.
3.
DNS propagation hasn't taken place yet. This will happen even with
your new web host's DNS in your domain record.
Solution: Wait 24-72 hours and contact your new web host if the problem
persists.
Why
can some people reach my new site but I can't?
Their
ISP has more up-to-date DNS records than your ISP. Be patient, as
your new site will appear within 24-72 hours.
Is
there some way to view/access my site even though the DNS hasn't changed
yet?
Yes.
You may access your site at http://ip.address/~username and you may
access the control panel at http://ip.address/config. If you don't
know the IP address of the server, please ask your web host for it.
Changing
DNS Settings
At
the main control panel menu, click the "DNS Menu" icon to
access the DNS settings.
Above
is an example of the DNS settings for site-helper.com. The next
sections provide information on changing A, CNAME, NS, MX, and PTR
records. In the meantime, it is important to understand how the
control panel handles hostnames.
Important:
There are two ways to enter a hostname:
1.
The full hostname followed by a period: full.hostname.com.
2.
The subdomain alone: full
For
example, the first record in the table above can read:
admin
A 216.194.67.119 or
admin.site-helper.com.
A 216.194.67.119
Both
records do the exact same thing. The sections below may discuss
only one method but either is
acceptable.
Hint:
If you are unsure how to enter a record, look at the existing records in
the table for guidance.
Records
Explained: A, CNAME, NS, MX, and PTR.
A
RECORDS
Address
(A) records direct a hostname to a numerical IP address.
For example, if you want mycomputer.yourdomain.com to point to
your home computer (which is, for example, 192.168.0.3), you would enter
a record that looks like:
Important:
You must put a period after the hostname. Do not put periods after
IP addresses.
CNAME
RECORDS
CNAME
allows a machine to be known by one or more hostnames.
There must always be an A record first, and this is known as the
canonical or official name. For
example:
yourdomain.com.
A 192.168.0.1
Using
CNAME, you can point other hostnames to the canonical (A record)
address. For example:
ftp.yourdoman.com.
CNAME yourdomain.com.
mail.yourdomain.com.
CNAME yourdomain.com.
ssh.yourdomin.com.
CNAME yourdomain.com.
CNAME
records make it possible to access your domain through ftp.yourdomain.com,
mail.yourdomain.com, etc. Without
a proper CNAME record, you will not be able to connect to your server
using such addresses.
Entering
a CNAME record
If
we wanted home.site-helper.com to point to site-helper.com, we could
enter the record in two ways:
The
first method allows you to simply enter the subdomain. Do not put
a period after the subdomain name.
The
second method requires you to enter the entire hostname, followed by a
period.
NAMESERVER (NS) RECORDS
NS
records specify the authoritative nameservers for the domain.
Important:
Changing NS records may cause your site to stop working. There is
generally no need to change NS records.
Entering
a NS record
The
first step is to delete the old NS records from the table above.
Then,
enter two new nameservers records. Be sure that the nameserver
hostname is followed by a period, as in this example:
Be
sure to put a period after the nameserver hostname in a NS record
(ns1.newnameserver.com. and not ns1.newnameserver.com ).
MX
RECORDS
Free
e-mail services such as everyone.net require that MX changes be made in
order for their software to work. This change allows mail destined
for your domain to be directed to their server. Please note that
changing MX records will prevent your current POP3 accounts, forwarders,
autoresponders, and mailing lists from functioning.
To
change the MX record, first access the "E-Mail Menu" from the
control panel. Then, click the "MX Records" icon.
First,
delete the old MX record by clicking the checkbox to next to the record
name and click "Delete Selected." There should now be no
MX records listed.
Next,
type in the hostname, followed by a period, given to you by the e-mail
provider. Then select the priority level (usually 10) from the
dropdown box on the right. The priority level will also be given
to you by the e-mail provider. Click "Add."
Note:
Be sure to put a period at the
end of the hostname.
To
restore the original MX settings, enter yourdomain.com. and priority 0
after deleting the other MX record.
PTR
RECORDS
Pointer
records (PTR) are used for reverse lookups. For
example, to make 192.168.0.1 resolve to www.yourdomain.com, the record
would look like:
1.0.168.192.in-addr.arpa PTR
www.yourdomain.com.
Note:
The IP address is reversed in the first field. Please use a period
after your hostname (second field).
The
“in-addr-arpa” method is the most frequently used.
Important:
PTR records are effective only if your site has its own IP address.
Important:
PTR records are only effective if
named.conf is manually edited and the proper zone information is
added. This can only be done by a root user (the server Admin).
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