Before I get into how an MX record works, you need to understand some DNS basics.
Computers are designed to work primarily with numbers. Human beings, on the other hand, tend to have an easier time understanding words. For example, if you wanted to visit my Web site, would you rather type www.brienposey.com or 24.235.10.4?
If you are like most people, it's a whole lot easier to remember a URL than an IP address. The problem is that if you enter a URL into your Web browser, your computer has no idea what you're talking about. Since it doesn't know what the URL means, it forwards it to a DNS server.
When you enter www.brienposey.com into a Web browser, your browser is smart enough to know that the site you're visiting exists somewhere within the brienposey.com domain. But, since brienposey.com isn't directly connected to your network, your browser has no idea where to find it.
There are often multiple DNS servers that service a domain. Multiple DNS servers might be used for load balancing, fault tolerance, or both. But, only one DNS server within a domain is considered authoritative.
The authoritative DNS server contains a read/write copy of the records database. Non-authoritative DNS servers are read-only. A Start of Authority (SOA) record points to the domain's authoritative DNS server. It also contains a sort of sequence number that is updated every time a change is made to the records contained within the zone. This helps non-authoritative DNS servers stay in sync with the authoritative DNS server.
Name Server (NS) records
A Name Server (NS) record is similar to an SOA record in that it points to the domain's DNS
A fully-qualified domain name (FQDN) is that portion of an Internet Uniform Resource Locator (URL) that fully identifies the server program that an Internet request is addressed to. The FQDN includes the second-level domain name (such as "whatis.com") and any other levels (for example, "www.whatis.com" or "www1.somesite.com"). The prefix "http://" added to the fully-qualified domain name completes the URL.
Computers are designed to work primarily with numbers. Human beings, on the other hand, tend to have an easier time understanding words. For example, if you wanted to visit my Web site, would you rather type www.brienposey.com or 24.235.10.4?
If you are like most people, it's a whole lot easier to remember a URL than an IP address. The problem is that if you enter a URL into your Web browser, your computer has no idea what you're talking about. Since it doesn't know what the URL means, it forwards it to a DNS server.
When you enter www.brienposey.com into a Web browser, your browser is smart enough to know that the site you're visiting exists somewhere within the brienposey.com domain. But, since brienposey.com isn't directly connected to your network, your browser has no idea where to find it.
An introduction to DNS records
When your Web browser checks the DNS server to find the IP address of the server hosting the Web site, it's actually looking for a record that lists the IP address of the Web site. DNS servers generally contain many different types of records. While it is beyond the scope of this tutorial to discuss all of them, here is an overview of some of the more important DNS records you should know about. Start of Authority (SOA) records There are often multiple DNS servers that service a domain. Multiple DNS servers might be used for load balancing, fault tolerance, or both. But, only one DNS server within a domain is considered authoritative.
The authoritative DNS server contains a read/write copy of the records database. Non-authoritative DNS servers are read-only. A Start of Authority (SOA) record points to the domain's authoritative DNS server. It also contains a sort of sequence number that is updated every time a change is made to the records contained within the zone. This helps non-authoritative DNS servers stay in sync with the authoritative DNS server.
Name Server (NS) records
A Name Server (NS) record is similar to an SOA record in that it points to the domain's DNS
Part 3: How to create an MX record
- To create an MX record on a Windows Server 2003 DNS server, select the DNS command from the server's Administrative Tools menu to open the DNS console.
- Navigate through the console tree to DNS -> your server -> Forward Lookup Zones -> your domain.
- Right click on the listing for your domain and select the New Mail Exchanger (MX) command. You will see the New Resource Record dialog box shown in Figure A. Figure A
Use the New Resource Record dialog box to create an MX record. - The first field on this dialog box asks for the name of a parent or child domain. In most cases, this field will be left blank.
- The fully qualified domain name (FQDN) is filled in automatically.
- Just below that is a field asking for the FQDN of the mail server -- not the mail server's IP address. What this means is that, unless you have a Host record in place for the mail server, the MX record isn't going to work.
As I explained in Part 3, an MX record won't work without a Host record in place, so let me explain how to set one up:
- In the DNS console, right click on your domain listing and select the New Host (A) command from the shortcut menu to view the dialog box shown in Figure B.
- Enter the server's name in the Name field. Be sure to use the simple name, not the fully qualified domain name (relevant -- not relevant.brienposey.com).
- Now enter the server's IP address and click the Add Host button. Figure B
Enter the server's name and IP address and click the Add Host button.
fully qualified domain name (FQDN)
A fully-qualified domain name (FQDN) is that portion of an Internet Uniform Resource Locator (URL) that fully identifies the server program that an Internet request is addressed to. The FQDN includes the second-level domain name (such as "whatis.com") and any other levels (for example, "www.whatis.com" or "www1.somesite.com"). The prefix "http://" added to the fully-qualified domain name completes the URL.
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