Knowledge Base

What is an IP Address?

An IP address (Internet Protocol address) is a unique numeric label assigned to every device connected to a network. It serves two purposes: identifying the device and providing its location so other devices know where to send data.

IPv4

IPv4 addresses are the original format, written as four numbers separated by dots. Each number ranges from 0 to 255:

93.184.216.34

IPv4 provides roughly 4.3 billion unique addresses. That sounded like plenty in the 1980s, but the pool has been effectively exhausted since 2011. Techniques like NAT (Network Address Translation) have extended its life, but IPv6 is the long-term solution.

IPv6

IPv6 addresses are 128 bits long, written as eight groups of four hexadecimal characters separated by colons:

2606:2800:0220:0001:0248:1893:25c8:1946

Leading zeros in a group can be dropped, and consecutive groups of all zeros can be replaced with :::

2606:2800:220:1:248:1893:25c8:1946

IPv6 provides approximately 340 undecillion (3.4 x 10^38) addresses — enough for every device on Earth to have billions of addresses.

Public vs. Private Addresses

Not every device needs a globally unique address. IP addresses are divided into two categories:

Public addresses

  • Globally unique and routable on the internet
  • Assigned by your hosting provider or ISP
  • What the outside world uses to reach your server
  • Example: 93.184.216.34

Private addresses

  • Used within local networks (homes, offices, data centers)
  • Not routable on the public internet
  • Multiple networks can reuse the same private ranges without conflict

Common private IPv4 ranges:

Range Addresses Typical use
10.0.0.0/8 16.7 million Large enterprise networks
172.16.0.0/12 1 million Medium networks
192.168.0.0/16 65,536 Home and small office networks

A router using NAT translates between private and public addresses, allowing many devices on a local network to share a single public IP.

CIDR Notation

CIDR (Classless Inter-Domain Routing) notation is a compact way to describe a range of IP addresses. It combines an IP address with a prefix length that indicates how many bits define the network portion:

93.184.216.0/24

The /24 means the first 24 bits are the network identifier, leaving the remaining 8 bits for host addresses. That gives 256 addresses (93.184.216.0 through 93.184.216.255).

Common prefix lengths:

CIDR Addresses Notes
/32 1 A single host
/24 256 A typical small subnet
/16 65,536 A large subnet
/8 16.7 million A massive network block

For IPv6, the same notation applies but with larger prefix lengths. A typical server allocation is a /64, which provides 18.4 quintillion addresses.

Static vs. Dynamic Addresses

  • Static — assigned permanently to a device. VPS servers use static IPs so they are always reachable at the same address
  • Dynamic — assigned temporarily by a DHCP server and may change over time. Common for home internet connections

All Sitequest VPS instances are assigned static public IPv4 and IPv6 addresses.

Reverse DNS (rDNS)

Standard DNS maps a domain name to an IP address (forward lookup). Reverse DNS does the opposite — it maps an IP address back to a domain name.

Reverse DNS uses PTR (Pointer) records. For example:

  • Forward: mail.example.com -> 93.184.216.34
  • Reverse: 93.184.216.34 -> mail.example.com

Reverse DNS matters for:

  • Email delivery — many mail servers reject messages from IPs without valid rDNS records
  • Logging and diagnostics — hostnames in logs are more readable than raw IPs
  • Reputation — services use rDNS to verify that an IP belongs to a legitimate organization

You can manage PTR records for your Sitequest VPS IPs from the dashboard. See Reverse DNS for details.

IP Addresses on Your VPS

When you create a VPS on Sitequest, it receives:

  • At least one public IPv4 address — used for SSH, web traffic, and all incoming connections
  • A public IPv6 address — for modern dual-stack connectivity
  • A gateway — the router address your server uses to reach the internet

You can view and manage your server's IP addresses, add additional IPs, and configure rDNS in the Network section of your dashboard.

Next Steps