DNS is a critical component of any child domain, and there are a number of best practices that should be followed in order to ensure its security and stability. In this article, we'll cover 10 of the most important DNS best practices for child domains.
Child domains are an important component of a domain name system (DNS) infrastructure. They provide a way to break up a large domain into smaller, more manageable pieces. Child domains also help to improve the security of a domain by creating a more segmented and secure network.
In this article, we will discuss 10 best practices for setting up and managing child domains in a DNS infrastructure. We will cover topics such as setting up the correct DNS records, delegating authority, and monitoring the health of the child domains. By following these best practices, you can ensure that your DNS infrastructure is secure and efficient.
Creating a separate DNS zone for each child domain allows the parent domain to delegate authority over its subdomains. This delegation of authority is done by creating resource records in the parent domain’s zone file that point to the authoritative name servers for the child domain. By delegating authority, the parent domain can ensure that only authorized users are allowed to make changes to the child domain’s DNS records.
The process of setting up a separate DNS zone for each child domain involves configuring the DNS server software on the host machine and then adding the appropriate resource records to the parent domain’s zone file. The first step is to create an A record for the child domain’s name server, which will allow clients to resolve the child domain’s address. Next, an NS record should be added to the parent domain’s zone file, pointing to the child domain’s name server. Lastly, any other necessary resource records such as MX or CNAME records should be added to the child domain’s zone file.
Having separate name servers for each domain allows the DNS records to be managed independently. This means that changes can be made to one domain without affecting the other, and it also makes troubleshooting easier since any issues with a particular domain can be isolated from the others.
To ensure that all of the parent and child domains have their own name servers, administrators should create an NS record in the parent zone file for each child domain. The value of this record should point to the name server responsible for managing the child domain’s DNS records. Additionally, the child domain should have its own A or AAAA record pointing to the IP address of the name server.
When a DNS query is sent to the Child Domain, it will first check its own records for an answer. If no answer is found, the query is forwarded to the root domain’s authoritative name server. This allows the Child Domain to take advantage of the root domain’s existing DNS infrastructure and ensures that all queries are answered quickly and accurately.
Configuring forwarders is relatively simple. In the DNS Manager console, select the Forwarders tab and add the IP address of the root domain’s authoritative name server. Once this is done, any queries sent to the Child Domain will be automatically forwarded to the root domain’s authoritative name server.
Conditional forwarding allows a DNS server to forward requests for subdomains of the parent domain to another DNS server. This is beneficial because it reduces the load on the Child Domain DNS server, as well as improving performance and reliability by allowing the DNS server to quickly resolve queries for subdomains without having to search through its entire database. Additionally, this can help improve security by preventing malicious actors from accessing sensitive information stored in the Child Domain DNS server. To set up conditional forwarding, administrators must first create an A record that points to the IP address of the other DNS server. Then, they must configure the Child Domain DNS server to forward all requests for subdomains to the other DNS server. Lastly, they should test the configuration to ensure that the setup is working properly.
Scavenging is a process that helps to keep the DNS zone clean by removing stale records. It works by periodically checking for resource records in the DNS zone that have not been updated within a certain time frame, and then deleting them. This helps to ensure that only valid records are present in the DNS zone, which can help improve performance and reliability of the domain’s name resolution services.
Enabling scavenging on the child domain’s DNS zones is relatively straightforward. The first step is to enable scavenging on the parent domain’s DNS server. Then, configure the same settings on the child domain’s DNS server. This includes setting the No-Refresh Interval, Refresh Interval, and Aging/Scavenging period values. Once these settings are configured, the scavenging process will begin automatically.
Monitoring DNS replication between the parent and child domains is important because it ensures that all changes made to the parent domain are replicated in the child domain. This helps ensure that any new records or updates to existing records are propagated throughout the entire network, which can help prevent issues such as name resolution errors.
To monitor DNS replication between the parent and child domains, administrators should use a tool like Microsoft’s Repadmin utility. This utility allows administrators to view the replication status of Active Directory objects between two domains, including DNS records. It also provides detailed information about any replication errors that may have occurred. Additionally, administrators can use this tool to manually initiate replication if needed.
ACLs are used to restrict access to the DNS zones, allowing only authorized users and systems to make changes. This helps protect against malicious actors who may try to modify or delete records in the zone. ACLs also help ensure that only valid requests are processed by the DNS server, reducing the risk of denial-of-service attacks.
To implement ACLs on a Child Domain DNS zone, administrators must first create an Access Control Entry (ACE) for each user or system that needs access to the zone. The ACE should specify which type of access is allowed (read, write, etc.) and from which IP address(es). Once all the necessary ACEs have been created, they can be applied to the zone using the appropriate command line tools. It’s important to note that any changes made to the ACLs will take effect immediately, so it’s important to test them thoroughly before applying them to production environments.
The SOA record is the Start of Authority record, which contains information about the domain name and its associated DNS server. It includes details such as the primary nameserver for the zone, the email address of the domain administrator, the serial number of the zone file, and the time to live (TTL) value.
When using Child Domain DNS, it’s important to ensure that the SOA record is updated in both the parent and child domains because this ensures that all changes made to the DNS records are propagated correctly throughout the entire network. This helps prevent any conflicts or inconsistencies between the two domains, ensuring that the DNS records remain up-to-date and accurate.
Updating the SOA record in both the parent and child domains can be done manually by editing the zone files on each domain’s DNS server. Alternatively, many DNS management tools provide an automated way to update the SOA record across multiple domains.
When a child domain is created, it inherits the DNS settings from its parent domain. This includes any records that have been configured in the parent zone file. By securely transferring the zone files from the parent to the child domain, administrators can ensure that all of the necessary records are present and up-to-date in the child domain’s DNS configuration.
Securely transferring zone files involves using secure protocols such as Secure Copy Protocol (SCP) or File Transfer Protocol over SSH (SFTP). These protocols encrypt data during transmission, ensuring that the information remains confidential and protected from malicious actors. Additionally, these protocols also provide authentication mechanisms which allow administrators to verify the identity of the sender and receiver before any data is transferred.
Once the zone files have been securely transferred, administrators should review them to make sure they contain all of the necessary records for the child domain. If any changes need to be made, they can be done directly on the child domain’s DNS server. This ensures that the child domain has an accurate and up-to-date DNS configuration.
Auditing the DNS records in the child domain helps to ensure that all of the necessary records are present and configured correctly. It also allows administrators to identify any potential security issues or misconfigurations, such as incorrect permissions on DNS objects or unauthorized changes to existing records.
To audit the DNS records in the child domain, administrators should first review the list of available DNS zones and record types. This will help them determine which records need to be checked for accuracy and completeness. Once this is done, they can use a variety of tools to check each record type for correctness. For example, they can use nslookup to query specific records, or they can use PowerShell scripts to automate the process. Additionally, they can use third-party software to scan the entire DNS zone for errors or inconsistencies. After completing the audit, administrators should document their findings and take corrective action if needed.