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DNS MANAGEMENT AT ROUGE
Here at rouge we spend most of our time designing and building websites, web applications and digital marketing materials. Very often this means getting down and dirty with domain names and domain configuration. This can been seen as complicated but actually it's really not; not at a level that's needed to make websites work. This is a simple guide and reference designed to demystify the technology - it's all you need to know!
WHAT IS A DOMAIN NAME
http:// - protocol (others include: ftp/ | https://)
rouge-media - domain name
.com - TLD – Top Level Domain
www - subdomain
Subdomains can be added at a server level and are treated as an independent domain in its own server space. Subdomains are useful if we’re creating a temporary development area or we want to subdivide the domain for other purposes. I.e.
Domains are under the jurisdiction of ICANN, the Internet Corporation for Assigned Names and Numbers which is responsible for creating new and maintaining current top-level domains.
WHAT IS AN IP ADDRESS
Every machine or device on a network (including the internet) has a unique address called an IP address, currently (IPV4) in this format: 18.104.22.1689 IP stands for Internet Protocol address. This of an IP address like a street address. Every machine has one. IPs can be permanent, usually for mail servers or websites but can also be dynamically assigned to individual machines or devices on a network or assigned by an ISP.
WHAT IS DNS
To avoid us having to remember IP address to find a website or email people, the Domain Name System (DNS) provides a way to match domain names with IP addresses.
I.e. rouge-media.com instead of 22.214.171.1249 or email@example.com instead of firstname.lastname@example.org
The simplified lookup process:
- Key in a domain name into a web browser or send an email
- Domain name servers around the world resolve the domain name and return the IP address. (See LOOKUP DETAIL section below to see this process in action.)
- Your device now knows the IP address and can contact the host (server)
The detailed lookup process:
- Application requests the A record for domain name www.rouge-media.com
- Client asks the configured DNS server for the A Record for www.rouge-media.com
- The recursive DNS server looks in its cache to see if already has a copy of the record. If the record isn't there it will then ask one of the root servers for the A record of www.rouge-media.com
- The Root DNS server doesn't have the record for www.rouge-media.com, it does know that the .com DNS server knows how to get it, it returns the location of the .com server in an NS (Name Server) record.
- The recursive then asks the .com DNS server for the A record of www.rouge-media.com, the .com DNS server doesn't have the A record, but knows that the DNS server ns1.express-hosting.co.uk knows how to get it and returns the NS records.
- The recursive server asks ns1.express-hosting.co.uk for the A record, since ns1.express-hosting.co.uk hosts the records for rouge-media.com it is able to provide this to the recursive server.
- The recursive server passes the A record back to the client.
- The client then uses the information returned in the A record to contact the web server and loads up the web page.
When a new domain is registered or DNS changes are made, the domain name servers around the world need to be made aware of the changes. The servers do not update in real time and some only update once a day or longer. This means that propagation of the DNS changes can take time to go round the planet.
A Name Server (NS) is a server with DNS software installed on it. It holds all the information about the records and where traffic is sent (via A records, MX records etc)
A name server takes this format: ns1.express-hosting.co.uk
An MX record tells senders how to send email for your domain.
Each MX record points to an email server that’s configured to process mail for that domain. There’s typically one record that points to a primary server, then additional records that point to one or more backup servers. For users to send and receive email, their domain's MX records must point to a server that can process their mail.
An MX Record typically looks like this:
rouge-media.com. MX 86400 0 rougemedia-com01c.mail.protection.outlook.com rouge-media.com. MX 86400 10 rouge.exnmailservers1.com rouge-media.com. MX 86400 20 rouge.exnmailservers2.com
- One primary and 2 backup servers
86400 – Time to Live (TTL) in seconds. In this case the server checks for changes every day. (86400 seconds = 1 day) 0 (10, 20) – Priority. The lowest number is tried by the server first.
Check your MX records here: http://mxtoolbox.com/
An A or Address record (also known as a host record) links a domain to the physical IP address of a computer hosting that domain's services. If a website is hosted on different server, and therefore with a different IP address, then a change to the relevant A record needs to be made.
An A record takes the form of an IP address: 126.96.36.199
Here is a useful reference to explain record types in more details: https://support.google.com/a/answer/48090?hl=en