SETTING UP YOUR DNS

setup your DNS is three easy steps

INTRODUCTION

Setting up your DNS can be a little daunting for the first time user.  This tutorial will explain how to setup your basic DNS service with Nettica.  If you're not a Nettica customer, this article will still provide with a wealth of information regarding DNS and how it works.

DNS is the Domain Name System for the Internet.  The real Internet is made up of IP addresses.  You've seen these before: 64.94.136.10, for example, is one of ours.  What DNS does is map a "friendly" name to IP addresses so they can be found both by humans and machines alike.  When you type in www.nettica.com into your browser the first thing it does is query your Internet Service Provider's DNS server for the IP address of our website.  If it finds a match, it returns the IP address to your browser, which then opens the page.  The same is true for your email.  When you send email, or you retrieve your own email, your email program looks up the IP address of your mail server, and then connects to that server to send or receive your mail.

This is a simplified explanation, we'll revise this view and go into more detail as we setup your DNS.

When you register a domain name, whether with Nettica or anyone else, there are two things you get.  The first is a WHOIS record which identifies you as the owner of the domain.  The second is the ability to set your DNS servers.  In order to use Nettica to manage your DNS, you must set your DNS registration to point to our servers.  Our DNS servers are:  DNS1.NETTICA.COM, DNS2.NETTICA.COM, DNS3.NETTICA.COM, DNS4.NETTICA.COM and DNS5.NETTICA.COM.  Once you make the changes it will take anywhere from 24 to 48 hours to propagate across the Internet.

Why does it take so long?  The reason goes back to the way the DNS system is setup.  The DNS system is a hierarchy with a set of root servers at the top.  When you open a browser and type in your website www.yourdomain.com  (line A), a DNS request first goes to your ISP's DNS server, and then percolates up to the top of the hierarchy (line B) if its a new request for the ISP DNS server.  At the top a root server determines that Nettica manages this domain (line C).  Since it's the first request of the day, it will cache that answer and not need to check on it again for another day.  So if someone else already manages your DNS, it will take a day for the root server to query again and find the new DNS owner.

This philosophy works the same down the hierarchy.  You query against your ISP's DNS server.  When it gets the result back from the root server that Nettica manages the DNS, it queries Nettica (line D) for the record and caches the result.  Your browser gets the IP address from the response and opens the page.  However, this time your ISP's DNS server is querying Nettica for a specific record, so you get to decide how long it caches the results.

STEP TWO:

SETTING UP YOUR DNS RECORDS

TTL - TIME TO LIVE

For each record, you can define a time to live (TTL).  This is the amount of time a DNS server caches one of your DNS records before it needs to be refreshed from its primary or secondary DNS servers (eg, our servers).  With Nettica we simplify this into two options: static or dynamic.  Dynamic entries expire after 1 minute, while static addresses will expire after 1 hour.

RECORD TYPES

Now that you have changed your DNS registration, you need to setup your domain.  There are six kinds of records you can define:  A, MX, and CNAME, Forward, TXT, and SRV.

A RECORD

An A record defines a host.  There are two things you can set for it: the IP address, and the time-to-live (TTL).  Certain records must be A records.  The root of your domain (eg, yourdomain.com), must be an A record.  If you are running an email server it must also be an A record.

MX RECORD

An MX record stands for Mail Exchange.  Typically, you need two records to define your email server:  the host (A) record (examples: mail.yourdomain.com, smtp.yourdomain.com, mx.yourdomain.com), and the MX record that points to it.  An MX record is used to locate your mail server when people send you email.   It is not used when you check your own email.  You use the host record (mail.yourdomain.com) to setup your email client.

The MX record itself contains three pieces of information.  The name of the domain (eg, you@yourdomain.com). The fully-qualified domain name of the mail server (mail.yourdomain.com), and the priority of the server (5,10,20, etc).  You can define multiple MX records with different priorities to designate backup mail servers.  Priority values normally range from 0-100, with the lower numbers being higher priority.

You do not need to define an MX record if you only have one IP address.  If there are no MX records defined for a domain, email servers use the host record for the root of the domain.

CNAME RECORD

CNAME records define aliases.  The most common alias record is for www.yourdomain.com.  It is not required that you use a CNAME record for your "www" alias, or any other record for that matter.  You can define your ftp server, web server, and any other server using a host record.  The tradeoff is convenience vs. lookup time.  The convience is that you only need to update one host record to update all the aliases as well.  However, it takes two lookups to resolve a CNAME, while only one lookup to resolve an "A" record.  Your site will be slightly faster using A records.  CNAME records cannot point to IP addresses.  They must point to fully-qualified domain names.

FORWARD RECORDS

A forwarding record is not a "real" DNS record type.  Instead, it is a built-in feature of Nettica which allows you to redirect your website to another.  This might be useful if you've registered a misspelling for your website and want to automatically forward customers to the right location.  It can also be used to redirect HTTP requests to an alternate port (useful if your ISP blocks port 80).  We support three forwarding methods. The first is a straight forward (302 redirect).  This is the most basic and universally accepted.  We also support 301 redirects.  Lastly, we support Masking, which does the redirect inside a frame, so that people see the pretty URL typed in, not the ugly underlying one.

TXT RECORDS

Text records (TXT) are commonly used to define SPF records for your email server.  While MX records define the incoming email server address, the Sender Policy Framework is used to define which outgoing email servers are allowed to send email on your behalf.  We support this initiative as a method of combating spam, and have added TXT records in order facilitate its rapid adoption.

SRV RECORDS

Service Location records (SRV) are also gaining popularity as a way to combat spam.  While still rarely used, we include this record to encourage adoption.

DNS SETUP EXAMPLE

This is a typical setup for a domain with a web server, mail server, and ftp server.  If your mail server is hosted by someone else, your MX record should point to the fully-qualified domain name of their mail server.

STEP THREE:

VERIFY YOUR DNS CONFIGURATION

Now that you have configured your domain, you should test it out to verify it works properly.  First, lets test the root domain.  Open a command prompt and type:

C:\>ping yourdomain.com

Pinging yourdomain.com [172.128.10.101] with 32 bytes of data:

Reply from 172.128.10.101: bytes=32 time=5ms TTL=127
Reply from 172.128.10.101: bytes=32 time=5ms TTL=127
Reply from 172.128.10.101: bytes=32 time=5ms TTL=127

C:\>

Repeat this for your mail server, and any other domain records.  Open a web browser and verify your web server is up.  Then send yourself an email to verify your MX record is setup correctly.  If you have a static IP address then you're finished.

STEP FOUR:

SETUP DYNAMIC DNS

If your server is not running on a static IP address, you will need a dynamic update client to fixup your DNS records whenever your IP address changes.  We provide a free Dynamic DNS Update Client to manage this.  Simply install the client and click "Add Hosts" to retrieve the list of hosts setup in your account.  You will be prompted for your Nettica account credentials.  This information will be saved locally so you do not have to enter it each time.  Select the host(s) running on your local machine.  Initially your account will be out of sync.  Click "Refresh" and "Update" to manually refresh update the IP address, or "Check for Changes" will do everything in a single step.  Once your initial sync is complete it will automatically update the IP addresses of your hosts when your external IP address changes.  The Nettica DNS Manager will automatically detect which method is best to determine your IP address (UPnP, polling, or direct connection).

CONCLUSION

You have now completely setup your DNS.  If you have any problems with your DNS service please contact Support immediately.

Buy Basic DNS Services

---

Feel free to link to this article either directly or indirectly.

Copyright � 2004-2010 Nettica Corporation All rights reserved.