Managing DNS Records – Part III – MX records and CName records
The final in our series of articles about DNS records, today we’re going to explore two of the most frequently used records. MX records and CName records are used with almost every domain and so it is vital you understand the difference, their impact on the system and how they affect the user experience.
MX Records will be used to set-up email on your own domain using many popular email services like using GMAIL to power your email, on your own domain. You can uses services like GMAIL to have your email be managed with the GMAIL system and still be your own domain like [email protected]
When you move a name to the default nameservers of your registrar, for instance to be able to manage text records or setup DNSSEC, you are now in the world of using CNAME and other records to manage your email and website. Normally, you would change nameservers to set-up web-hosting, but may lose the ability to add your own text records for listing on marketplaces. Understanding CNAME and MX records will allow you to set-up website hosting – and still manage TXT records.
For those that haven’t read our previous articles, let’s start with a quick recap of what a DNS record is…
A DNS record, sometimes known by the term zone file is a set of text-based instructions created to deliver information about a specific domain. The information often includes the IP address that is connected with the domain, as well as how specific requests should be handled.
These records are in a text file format and written in DNS syntax, meaning that each record has a collection of characters that acts as a command telling a DNS server what to do. Every domain must have certain DNS records that are required for a website to operate correctly.
If you’d like to know more about the wide range of DNS records then you can visit a helpful resource here.
What is a DNS MX record?
An MX record is a mail exchange record and in its simplest form directs emails to a specific email server. These records tell the system how an email message must be routed, following the Simple Mail Transfer Protocol (SMTP).
An interesting feature of MX records is the priority value. When creating a record, you may have multiple email servers that you wish to send emails to in a particular order or share them equally to balance the workload.
If you have two options, with one record having a lower priority than the other then this will be the preferred process. Should the preferred process fail for any reason, then the system will default to the next lowest priority number.
What do we need to know about how MX records work?
Compared to some of the other DNS records we’ve discussed, MX records are a relatively simple concept to understand. However, it is good to know some of the underlying processes and requirements for MX records in case you need to deal with them at a more technical level.
How does querying an MX record work?
The software responsible for querying an MX record is called MTA software. This stands for Message Transfer Agent software.
After a user clicks send on their email, this MTA software comes into play sending a DNS query to find out the specific mail servers for the recipients of the email. After this, the MTA software will establish an SMTP connect, in the priority order that the MX record states.
Where should you point an MX record to?
MX records need to point straight to the server’s A record, or AAAA record. You can find out more about this type of record in one of our previous articles here. It is important to note that you must not point to a CNAME record, as this is expressly forbidden by documentation that defines how MX records operate.
Why do people use a backup MX record?
One of the main reasons why people use a backup MX record (discussed above when we explored priority values) is that in the event a mail server doesn’t work then the system will still work.
It can be a useful way to balance the workload of multiple servers and ensure users experience a consistent service. This idea of balancing the workload is known as load balancing and for those wanting to look at it in more detail, we suggest visiting this website.
What is a CNAME record and what do we need to know about them?
The second part of this article is about the CNAME record and in particular how the DNS system utilises it. Anyone who operates multiple domains, services or is a web professional will have used these before, but for others who are new to domain management and domain trading let’s start with a definition.
So what exactly is a CNAME record?
CNAME standards for Canonical Name and this record allows a domain owner to create an alias from one domain name to a second domain name. This functionality allows us to use CNAME records in a few different ways including:
- If you wish to register the same domain in multiple countries but point those individual country domains to a central domain such as a .com or .net.
- If an organisation has multiple websites then they can all point to the main website.
- If you wish to use separate names for specific services such as email or FTP.
- If you want to provide specific subdomains to customers on a provider’s main domain (for example customer1.hostname.com), but then point it to a customer’s personal domain.
Are there restrictions with CNAME records?
There are some specific restrictions when we deal with CNAME records and it is important to be aware of them before you start utilising them. These restrictions include:
- You cannot place a CNAME record at the level of the root domain. This is because the root domain must use a DNS Start Of Authority to point to an IP address.
- A CNAME record must only point to a domain name and not an IP.
- You must not point an NS record or an MX record to a CNAME alias.
- It is advisable not to use a CNAME record for any domains that are used for email purposes. It can have negative results for mail servers.
What record types are normally used with a CNAME record?
In general, you will find that the CNAME record is used with two other types of records and these are ALIAS and A records. Let’s break down the differences between these two alternative records.
An A record is used to map a hostname to an IP address (or multiple IP addresses). This differs from a CNAME record because these map from hostname to a hostname.
Very similar to a CNAME record, it maps a hostname to a hostname. However, the key difference is that ALIAS records allow the possibility of other DNS records being on the same hostname. This means you could apply it at the root domain level, unlike a CNAME record.
A final thought on DNS records
Throughout this series of articles on DNS records, we’ve tried to share the most important pieces of information, explain their relevance to the world of domain ownership and in general, start to get to the bottom of what can be a complex part of domain management.
In most cases, domains can be managed easily through domain registrars and domain host dashboards. If ever in doubt, this is a great place to start but there are also some fantastic user guides out there on how to make a new record or amend an existing one.
Keep this in mind when searching for that next domain to buy on our Cloudname trading platform, so that you can connect it to your existing website or manage emails accordingly.
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