How to create and update DNS records?
What is a DNS record?
The DNS records (also known as zone files or resource records) are the constituent files of a Zone or a Domain that carry the essential instructions that help the DNS resolver quickly resolve the DNS queries for a domain. These files are hosted on authoritative DNS servers and deliver information about a domain or its subdomains such as the associated list of IP addresses of the dedicated hosts configured for delivering responses for the domain and the necessary query processing instructions to deliver optimized response for that domain.
Anytime an enduser searches for a URL from their web browser, it is the browser that makes a DNS query to the local public resolver. The resolver in turn forwards the query to the DNS servers. The set of instructions in a DNS record hosted on DNS servers helps the DNS resolver to translate a URL into a unique IP address by navigating the DNS traffic to a specific web server. Each DNS record is identified by a unique domain name and the record type. It is the record type that identifies the nature of the information included in the record.
Types of DNS records in ManageEngine CloudDNS
ManageEngine CloudDNS offers complete DNS management support for A, AAAA, CNAME, ALIAS, ANAME, CAA, DS, MX, NS, PTR, SPF, SRV, and TXT records.
Creating DNS records by importing and exporting zone files
CloudDNS enables you to quickly create all of the records for CloudDNS hosted zone by importing a zone file as JSON and BIND, which are the two standard formats used to represent zone files in a text format.
To create DNS records by importing a zone file in JSON or BIND format:
- Get the zone file exported and saved as JSON or BIND files from the DNS service provider currently servicing your domain. Make sure the zone file is in RFC-compliant format.
- In CloudDNS, create a new zone or select a zone by clicking on its name.
- Once you are inside the new zone click the Import button in the top right corner.
- Choose if you want to import the zone file as a JSON or a BIND file.
On choosing the desired format, the Import window appears where you can paste the contents of your zone file inside the text box.
Click the Import button at the bottom to start importing. You may have to wait a few minutes for the records to be created as it depends on the number of records in your zone file.
The same process is followed to export your zone files in CloudDNS as JSON or BIND files by clicking on the Export button in the top right corner. On clicking the Export button, the zone files are automatically downloaded as text files with the respective domain name in JSON or BIND format.
Creating DNS records with customized configurations
ManageEngine CloudDNS also enables you to save different values and settings for each DNS record you create within a zone.
Select Domains menu from the menu bar on the left window pane.
In the Domains page, create a new domain or click on the domain name of your choice from the list of the domains that you intend to create DNS records for.
This will take you inside that particular domain, displaying various types of records supported by CloudDNS like A, AAAA, ANAME, CNAME, etc.
Select the relevant record type you'd like to configure for your domain and click on it.
To create a new record under the chosen record type:
Click on the blue Add button at the extreme right corner of the table header under the chosen record type.
The Create page for the chosen record type displays requesting you to key in the essential details for the new record.
Enter a relevant name for the DNS record.
The Time-To-Live (TTL) value comes pre-filled, if you've enabled an SOA template beforehand or else you can modify the value as per your requirements. More on SOA template here.
The Time-To-Live(TTL) attribute specifies the total number of seconds the local resolver ought to cache the response for a record before requesting a new one.
The Maxhost attribute enables you to specify the maximum number of active hosts to which the DNS traffic for the particular domain can be directed to. Maxhost carries a default value: 1
The Filters attribute defines the scope of your domain. Filters are rules that you can apply to the records to direct the traffic based on the location, ASN, subnet, IP protocol, or IP address of the end-users.
Only one filter can be associated with a single DNS record. First a record must be created with the filter: world_default before applying any other filters.
Record Modes for dynamic load balancing
While specifically creating A, AAAA, ANAME, CNAME, or ALIAS-type records for a domain, it's mandatory to specify a mode for the record. This mode indicates the type of load balancing strategy applicable for the record. The record mode is set as either standard, failover, or round robin.
Scroll down to find more information on record modes below .
CloudDNS enables you to specify a group of multiple Target IP addresses or Hosts which serve the incoming traffic from the client with relevant responses.
Click on Add IP.
CloudDNS enables you to configure multiple hosts to provide responses for a domain by clicking Add IP. To configure multiple hosts for a DNS record click on Add IP after each entry. The options for configuring the response delivery hosts vary depending on the record Mode you choose. It is the record mode configuration that determines the host(s) for sending optimized response based on the health and priorities attached to each host.
The standard record mode specifies no special configurations and simply serves the IPs or hosts configured for a record.
For the record Mode Standard, The Add IP window appears requesting only the IP address of the response delivery host, as the standard mode just serves the IP(s) and Host(s) configured for the record. No special configurations come under the standard record mode.
The Round-Robin mode distributes the incoming traffic across a group of designated hosts on a rotational basis so that every server in the group gets a chance to serve your traffic. You can also assign weights for each server. The weight value indicates the priority of a host in comparison to other hosts within the target server group. In case identical weight values are assigned to multiple hosts in the target server group, the incoming request is processed in a round robin fashion. This weighted round robin mode, integrated with health monitoring checks, eliminates any trace of instability or downtime.
For the record mode Round- Robin, the Add IP window appears requesting not only the IP address of the host but also the associated weight for that host. Assign an appropriate weight value between 0 to 255 designates a priority level among the host servers group that you create.
The failover record mode option is available only for A, AAAA, CNAME, or ANAME records. This mode guarantees strong record redundancy to improve availability and resilience. Choosing this mode will need the addition of extra IPs/hostnames for failover configuration.
To specify priority levels among endpoints, CloudDNS offers two options for specifying priority levels among endpoints: 1) Weight-based failover record mode and 2) Priority-based failover record mode.
Weight based failover option
The weight-based failover option allows you to route traffic to multiple hosts under a single domain in various proportions, based on the weights assigned to each host. Weights assigned to hosts in the range of positive integers between 1 and 255, determine the amount of traffic routed to each resource, with higher weights indicating higher priority.
Each host is assigned a relative weight that decides the amount of traffic that is to be sent to each host compared to the other active hosts in the group. CloudDNS serves the query based on the host's weight as a proportion of the total weight for all the active hosts in the group. With this approach, you can seamlessly scale up or down and balance the distribution of traffic among the group of active hosts.
Priority based failover option
The priority based failover option lets you to assign priority levels to each of your hosts configured under the record. These priority levels are positive integers between 1 and 255, with the highest number indicating the highest priority. No two hosts can share the same priority level. If the active host with the highest priority experiences an outage and becomes unavailable, the host with the next highest priority level will seamlessly take over to serve the queries for the domain.
To ensure only healthy endpoints are associated, it is also mandatory to specify a suitable monitor along with these configurations.
Global Traffic Directed Domains (GTD)
ManageEngine CloudDNS maintains an IP database identifying the location of the requester or the end user at the continent, country, and state/province levels to connect end users to the closest resource by means of Global Traffic Directed Domains(GTD), which rapidly delivers the domain in demand from the closest resource to establish best performance. This can be activated by dragging the Closest toggle.
To enable GTD for the chosen DNS record drag the Closest toggle to green. This directs the source IP (IP of the enduser or the domain visitor) traffic requesting the domain to a target IP located closest to the Source IP's location.
After creating a relevant DNS record for your domain, you can easily add or modify the response delivering hosts along with the associated filters, monitors and record mode configurations to re-define the logic ManageEngine CloudDNS deploys to steer the DNS traffic to the host that delivers optimized response to the query.