Overview
With IONOS Cloud Domain Name System (DNS), you can publish your domain names to the global DNS. The feature is built around the concept of DNS zones and records that can be managed through both the Cloud DNS API and the Data Center Designer (DCD) including an option to grant additional users with privileges to manage these DNS zones and records.
Concepts
DNS: Refers to a system that converts domain names into IP addresses. The DNS translates domain names into numeric IP addresses that computers can understand and use to access websites or other internet resources.
Name Servers: Name Servers or DNS Servers are parts of the computer's DNS infrastructure and store DNS records for a particular domain name. They provide information about the IP address or other resources associated with a domain name. When you request access to a domain, your device queries the domain's name servers to resolve the corresponding IP address.
DNS Zone: A DNS zone is an administrative unit that contains DNS records for a specific domain. It specifies the authoritative DNS servers for that domain and their IP addresses.
DNS Record: A DNS record is a set of instructions stored on DNS servers that maps domain names to IP addresses and vice versa. They are used to help route internet traffic, provide email services, and facilitate other internet functions. DNS records come in various formats, such as Address (A), IPv6 Address record (AAAA), Canonical Name (CNAME), Mail Exchange (MX), Text (TXT), and so on. Every DNS record has a type (name and number), an expiration time (time to live (TTL)), and type-specific information.
Reverse DNS: Reverse DNS is a method of resolving an IP address to a domain name. It is the opposite of the standard DNS lookup, which resolves a domain name to an IP address. You can verify the authenticity of an IP address by checking whether the hostname associated with the IP address matches the expected domain. Reverse DNS operates through PTR (Pointer) records, which are special DNS records.
PTR records: A PTR record contains a hostname associated with an IP address. It is a crucial tool for security and spam prevention. Network administrators and email servers rely on reverse lookups to verify the legitimacy of incoming connections. For instance, email servers use reverse DNS to authenticate the sender's IP address against its claimed domain, effectively filtering out suspicious or fraudulent emails. In short, reverse DNS with PTR records provides a robust layer of verification and security by accurately matching IP addresses with hostnames, thereby ensuring the reliability and trustworthiness of network connections.
Secondary DNS Zone: A secondary DNS zone is a read-only copy of a primary DNS zone. It holds the same DNS records for a domain and helps distribute the load and ensure redundancy. If the primary DNS server experiences issues, the secondary zone can still provide accurate DNS information, ensuring continuous availability for domain name resolution.
DNSSEC Keys: DNSSEC keys are cryptographic keys used to enhance the security of the DNS. DNSSEC keys are generated as pairs: a private key and a corresponding public key. The private key is kept secure, while the public key is shared in DNS records. These keys are crucial for validating DNS responses, preventing tampering, and ensuring the security of DNS information.
Time-to-live (TTL): TTL is a DNS record setting that specifies how long a DNS resolver should cache the results of a query before querying the DNS server again for updated information.
Domain Registrar: A domain registrar is a company or an organization that manages the registration of domain names on the Internet. The Internet Corporation for Assigned Names and Numbers (ICANN) accredited registrars are responsible for ensuring the accuracy and validity of domain name registrations. Domain registrars include IONOS, Strato, Fasthosts, Arsys, Home.pl, and World4You.
Forward and Reverse DNS lookups
A forward DNS lookup zone converts a name to an IP address or another name. You can use it when you want to resolve a domain name. In the following example, a user sends a domain to the DNS server to find its IP address. The DNS server looks for the relevant IP address mapped to the respective domain and returns the IP address. The forward zone contains all the records of domain names to their IP addresses.
Similarly, you can use a reverse DNS lookup to convert an IP address to a domain name. The DNS server finds the mapped domain name and returns the respective domain name to the user. A reverse DNS lookup zone contains all the records of IP addresses to their domain names.
Reverse lookup zones can be helpful for troubleshooting issues. For example, businesses can use spam filters to track and block IP addresses with a failed reverse DNS lookup or if the lookup contains suspicious keywords.
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