DNS Records
Complete DNS record set for this domain — A, AAAA, CNAME, MX, NS, TXT, SPF, SRV, PTR, and SOA records.
A Records (IPv4)
A Records (IPv4)
An A (Address) record maps a domain name to an IPv4 address, allowing browsers and other clients to locate the server hosting a website or service. This is the most fundamental DNS record type for connecting human-readable domain names to machine-readable IP addresses.
Common Uses
- Pointing a domain (example.com) to a web server's IPv4 address
- Creating subdomains that resolve to specific servers (blog.example.com, mail.example.com)
- Load balancing by returning multiple A records for the same domain (round-robin DNS)
Valid Settings
Any valid IPv4 address in dotted-decimal notation (e.g., 192.0.2.1). Values must be in the range 0.0.0.0 to 255.255.255.255. Multiple A records can exist for the same hostname.
History
A records were defined in RFC 1035 in 1987 as part of the original DNS specification by Paul Mockapetris. They remain the primary method for IPv4 address resolution and are the most commonly queried DNS record type.
A Records (IPv4)
An A (Address) record maps a domain name to an IPv4 address, allowing browsers and other clients to locate the server hosting a website or service. This is the most fundamental DNS record type for connecting human-readable domain names to machine-readable IP addresses.
Common Uses
- Pointing a domain (example.com) to a web server's IPv4 address
- Creating subdomains that resolve to specific servers (blog.example.com, mail.example.com)
- Load balancing by returning multiple A records for the same domain (round-robin DNS)
Valid Settings
Any valid IPv4 address in dotted-decimal notation (e.g., 192.0.2.1). Values must be in the range 0.0.0.0 to 255.255.255.255. Multiple A records can exist for the same hostname.
History
A records were defined in RFC 1035 in 1987 as part of the original DNS specification by Paul Mockapetris. They remain the primary method for IPv4 address resolution and are the most commonly queried DNS record type.
Maps the domain to IPv4 addresses.
| Address | Name | TTL |
|---|---|---|
| 140.82.114.3 | lb-140-82-114-3-iad.github.com | 300s |
AAAA Records (IPv6)
AAAA Records (IPv6)
An AAAA (quad-A) record maps a domain name to an IPv6 address, serving the same purpose as A records but for the newer 128-bit IPv6 addressing system. As IPv4 addresses become exhausted, AAAA records are increasingly important for modern internet infrastructure.
Common Uses
- Enabling IPv6 connectivity for websites and services
- Dual-stack configuration where both A and AAAA records exist for the same domain
- Future-proofing infrastructure as the internet transitions from IPv4 to IPv6
Valid Settings
Any valid IPv6 address in colon-hexadecimal notation (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334 or shortened as 2001:db8:85a3::8a2e:370:7334). Addresses are 128 bits represented as eight groups of four hexadecimal digits.
History
AAAA records were defined in RFC 3596 in 2003 to support IPv6 addressing. The name 'AAAA' was chosen because IPv6 addresses are four times larger than IPv4 addresses (128 bits vs 32 bits).
AAAA Records (IPv6)
An AAAA (quad-A) record maps a domain name to an IPv6 address, serving the same purpose as A records but for the newer 128-bit IPv6 addressing system. As IPv4 addresses become exhausted, AAAA records are increasingly important for modern internet infrastructure.
Common Uses
- Enabling IPv6 connectivity for websites and services
- Dual-stack configuration where both A and AAAA records exist for the same domain
- Future-proofing infrastructure as the internet transitions from IPv4 to IPv6
Valid Settings
Any valid IPv6 address in colon-hexadecimal notation (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334 or shortened as 2001:db8:85a3::8a2e:370:7334). Addresses are 128 bits represented as eight groups of four hexadecimal digits.
History
AAAA records were defined in RFC 3596 in 2003 to support IPv6 addressing. The name 'AAAA' was chosen because IPv6 addresses are four times larger than IPv4 addresses (128 bits vs 32 bits).
Maps the domain to IPv6 addresses.
| Address | Name | TTL |
|---|---|---|
| 64:ff9b::8c52:7203 | lb-140-82-114-3-iad.github.com | 300s |
PTR Records (Reverse DNS)
PTR Records (Reverse DNS)
A PTR (Pointer) record performs reverse DNS lookup by mapping an IP address back to a hostname, essentially the opposite of A and AAAA records. PTR records are stored in special reverse lookup zones.
Common Uses
- Email server verification (many mail servers reject email from IPs without valid PTR records)
- Network troubleshooting and logging (converting IP addresses to readable hostnames)
- Security and abuse investigations (identifying the organization behind an IP address)
Valid Settings
A fully qualified domain name (FQDN) that the IP address resolves to. PTR records are stored in reverse zones: IPv4 uses '.in-addr.arpa' (e.g., 1.2.0.192.in-addr.arpa for 192.0.2.1).
History
PTR records were defined in RFC 1035 in 1987 as part of the original DNS specification. Reverse DNS became increasingly important in the 1990s for email verification and spam prevention.
PTR Records (Reverse DNS)
A PTR (Pointer) record performs reverse DNS lookup by mapping an IP address back to a hostname, essentially the opposite of A and AAAA records. PTR records are stored in special reverse lookup zones.
Common Uses
- Email server verification (many mail servers reject email from IPs without valid PTR records)
- Network troubleshooting and logging (converting IP addresses to readable hostnames)
- Security and abuse investigations (identifying the organization behind an IP address)
Valid Settings
A fully qualified domain name (FQDN) that the IP address resolves to. PTR records are stored in reverse zones: IPv4 uses '.in-addr.arpa' (e.g., 1.2.0.192.in-addr.arpa for 192.0.2.1).
History
PTR records were defined in RFC 1035 in 1987 as part of the original DNS specification. Reverse DNS became increasingly important in the 1990s for email verification and spam prevention.
Pointer records mapping IP addresses back to hostnames.
| Hostname | Name | TTL |
|---|---|---|
| lb-140-82-114-3-iad.github.com | 3.114.82.140.in-addr.arpa | 30s |
| Type | Value | Name | TTL |
|---|---|---|---|
| PTR | lb-140-82-114-3-iad.github.com | 3.114.82.140.in-addr.arpa | 30 |
| A | 140.82.114.3 | lb-140-82-114-3-iad.github.com | 300 |
| AAAA | 64:ff9b::8c52:7203 | lb-140-82-114-3-iad.github.com | 300 |