DNS record types and routing policies — AWS Route 53 hosted zones

DNS Record Types:

1. A Record (Address Record):

• Maps a domain name to an IPv4 address.
• Example: example.com -> 192.168.1.1
• Usage: Pointing a domain name to a web server or other resources with IPv4 addresses.

2. AAAA Record (IPv6 Address Record):

• Maps a domain name to an IPv6 address.
• Example: example.com -> 2009:er4::1
• Usage: Enabling IPv6 connectivity for websites and services.

3. CNAME Record (Canonical Name Record):

• Creates an alias for one domain name to another.
• Example: www.example.com -> example.com
• Usage: Redirecting traffic, managing multiple subdomains, pointing to resources on external domains.

4. CAA Record (Certification Authority Authorization):

• Specifies which certificate authorities (CAs) are authorized to issue certificates for a domain.
• Example: example.com CAA 0 issue "letsencrypt.org"
• Usage: Enhancing security by controlling CA issuance for your domain.

5. MX Record (Mail Exchange Record):

• Specifies the mail server responsible for receiving emails for a domain.
• Example: example.com MX 10 mail.example.com
• Usage: Directing email traffic to the correct mail servers.

6. NS Record (Name Server Record):

• Specifies the authoritative name servers for a domain.
• Example: example.com NS ns4.example.com
• Usage: Delegating DNS management to specific name servers.

7. PTR Record (Pointer Record):

• Used for reverse DNS lookups, mapping an IP address back to a domain name.
• Example: 192.168.1.1 PTR example.com
• Usage: Troubleshooting, email delivery, network security.

8. SOA Record (Start of Authority Record):

• Contains essential information about a domain, including the primary name server, administrator’s email address, and zone metadata.
• Example: example.com SOA ns1.example.com admin.example.com 2024255556 7200 3600 12034500 3600
• Usage: Defining administrative and technical details of a DNS zone.

9. SPF Record (Sender Policy Framework):

• Helps prevent email spoofing by specifying authorized senders for a domain.
• Example: example.com SPF "v=spf1 a mx include:_spf.google.com ~all"
• Usage: Improving email deliverability and preventing spam.

10. SRV Record (Service Record):

• Specifies the location of specific services within a domain.
• Example: _sip._tcp.example.com SRV 0 5 5060 sipserver.example.com
• Usage: Locating services like VoIP, instant messaging, and gaming servers.

11. TXT Record (Text Record):

• Stores arbitrary text information about a domain.
• Example: example.com TXT "v=spf1 include:_spf.google.com ~all"
• Usage: Verification of domain ownership, SPF records, DKIM records, and DMARC records.

Routing Policies:

1. Simple Routing:

• Routes all traffic to a single resource, such as an IP address, a load balancer, or an S3 bucket.
• Usages: Simple website hosting, basic DNS configuration, single-endpoint applications.

2. Failover Routing:

• Routes traffic to a primary resource, and if it becomes unavailable, automatically redirects traffic to a secondary resource.
• Usages: Disaster recovery, high availability setups, ensuring service continuity during primary resource outages.

3. Geolocation Routing:

• Routes traffic based on the geographic location of the user, directing users to resources in their region or closer to them for improved performance.
• Usages: Content personalization, global content distribution, region-specific services, latency reduction for global audiences.

4. Latency-Based Routing:

• Routes traffic to the resource with the lowest network latency for the user, optimizing performance and reducing response times.
• Usages: Applications sensitive to latency, and geographically distributed resources, ensuring optimal user experience across different regions.

5. Weighted Routing:

• Routes traffic to multiple resources in the proportions you specify, enabling load balancing and traffic distribution.
• Usages: Scaling applications across multiple servers, distributing traffic across different regions or availability zones, and handling variable workloads.

6. Multivalue Answer Routing:

• Returns multiple IP addresses or AAAA records in response to DNS queries, allowing clients to load balance requests across multiple resources.
• Usages: Client-side load balancing, distributing traffic across multiple servers for improved performance and redundancy.

7. IP-Based Routing:

• Routes traffic based on the IP address of the user, allowing for selective routing based on network origin.
• Usages: Internal network routing, restricting access to resources based on IP addresses, security segmentation, and access control.