- Dotted Decimal
- The most common human-readable IPv4 format, dividing the 32-bit address into four 8-bit groups, each converted to a decimal number 0–255 and connected by dots, e.g., 192.168.1.1.
- Decimal Integer
- Treating the 32-bit IPv4 address as a single unsigned integer in the range 0–4294967295. Commonly used for database storage (e.g., MySQL's INET_ATON function) and range comparison.
- Binary
- The raw 32-bit binary representation of an IPv4 address, with 8 bits per octet. Bitwise operations for subnet masks and CIDR prefixes all occur at the binary level.
- Hexadecimal
- An 8-digit hexadecimal representation prefixed with 0x, where each 2 digits correspond to one octet. Commonly seen in packet capture analysis (e.g., Wireshark) and low-level protocol debugging.
- Octet
- Each dot-separated 8-bit segment in an IPv4 address is called an octet, with values from 0–255. Four octets make up the complete 32-bit address.
- Network Byte Order
- TCP/IP protocols specify Big-Endian for transmitting multi-byte data, meaning the most significant byte comes first. The writing order of dotted decimal is consistent with network byte order.
- CIDR (Classless Inter-Domain Routing)
- A notation using a /prefix length to indicate network bits, e.g., /24 means the first 24 bits are network bits and the last 8 bits are host bits.
- Subnet Mask
- A 32-bit binary number where network bits are all 1s and host bits are all 0s, used to distinguish the network portion from the host portion of an IP address, e.g., 255.255.255.0.
- Wildcard Mask
- The bitwise NOT of a subnet mask, where 0 means must match and 1 means ignore. Used in ACL and routing configurations, e.g., 0.0.0.255 corresponds to /24.
- INET_ATON / INET_NTOA
- Classic function names for IP address-to-integer conversion. ATON (ASCII to Number) converts dotted IP to integer; NTOA (Number to ASCII) does the reverse. Available in MySQL, PHP, and C.
