Notes
DNS Concepts
What is DNS
Check other pages about DNS and DNS_Enumeration.
DNS Server
DNS Records
| Types | Use |
|---|---|
| A (Address) | Maps a hostname to an IP address |
| SOA (Start of Authority) | Identifies the DNS server responsible for the domain information |
| CNAME (Canonical Name) | Provides additional names or aliases for the address record |
| MX (Mail Exchange) | Identifies the mail server for the domain |
| SRV (Service) | Identifies services such as directory services |
| PTR (Pointer) | Maps IP addresses to hostnames |
| NS (Name Server) | Identifies other name servers for the domain |
| TXT (Text) | Add Text data in DNS Records |
Dynamic DNS
Dynamic DNS (DDNS) is a service that keeps the DNS updated with a web property’s correct IP address, even if that IP address is constantly being updated.
In the early days of the Internet, IP addresses rarely changed, which made management of domains a lot simpler. But the rapid growth of the web and home computers with Internet access created a shortage of available IP addresses. This led to the Dynamic Host Configuration Protocol (DHCP), which lets ISPs assign IPs to their users dynamically. ISPs will typically maintain a shared pool of IP addresses and assign or ‘lease’ them to users as needed, for the duration of their connection or until a maximum amount of time has been reached. Although the introduction of IPV6 alleviated the IP address shortage, ISPs still often use DHCP because it is more cost-efficient than providing static IPs.