Validate IPv4 and IPv6 addresses instantly with detailed analysis. Get comprehensive information about address types, classes, and formatting with real-time feedback and educational content.
Real-time IPv4 and IPv6 address validation with detailed error messages
Get address class, type, scope, and formatting information
Learn IP address formats, classes, and common validation errors
Validate IPv4 and IPv6 addresses instantly. Get detailed information about address types, classes, and formatting with real-time feedback and educational content.
IPv4 addresses consist of four octets (numbers from 0-255) separated by dots. Each octet represents 8 bits, making IPv4 addresses 32 bits total.
10.0.0.0/8 - 10.0.0.0 to 10.255.255.255172.16.0.0/12 - 172.16.0.0 to 172.31.255.255192.168.0.0/16 - 192.168.0.0 to 192.168.255.255IPv6 addresses are 128 bits long and written as eight groups of four hexadecimal digits, separated by colons. They can be compressed using double colons (::) to represent consecutive zeros.
2001:0db8:0000:0000:0000:0000:0000:00012001:db8::12001:db8::192.168.1.132-bit addresses with 4.3 billion possible combinations
Format: xxx.xxx.xxx.xxx (e.g., 192.168.1.1)
128-bit addresses with virtually unlimited combinations
Format: xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx
Always validate IP addresses on both client and server sides. Use proper regex patterns for initial format checking, then perform range validation for octets (IPv4) or groups (IPv6). Consider using libraries for production applications to handle edge cases and ensure RFC compliance.
IPv4 addresses are divided into classes based on the first octet value. This classful addressing system was the original method for organizing IP address space, though modern networks primarily use CIDR notation.
Note: While classful addressing is largely historical, understanding classes helps identify address types and is still relevant for network troubleshooting and legacy systems.
Use Case: Originally designed for very large organizations like major corporations and government agencies. Most Class A addresses are now allocated to large ISPs and cloud providers.
Use Case: Medium-sized organizations like universities, large companies, and regional ISPs. Provides a good balance between network count and host capacity.
Use Case: Small networks like home offices, small businesses, and branch offices. Most common class for end-user networks and the basis for most home router configurations.
Look at the first octet of an IPv4 address to determine its class
Private IP addresses are reserved for use within private networks and are not routable on the public internet. They were defined in RFC 1918 to conserve public IPv4 address space and provide security through network isolation.
Best Practice: Use 10.x.x.x for large networks that need extensive subnetting. Popular with enterprises and cloud environments due to the massive address space.
Best Practice: Ideal for medium networks that need more addresses than Class C but don't require the full Class A range. Commonly used by cloud providers and containerization platforms.
Best Practice: Most familiar to home users and perfect for small networks. Default choice for consumer routers and simple network setups.
169.254.0.0/16 Automatic Private IP Addressing
Used when DHCP fails, auto-assigned by OS
127.0.0.0/8 Local host communication
127.0.0.1 is the most common loopback address
100.64.0.0/10 ISP shared address space
Used by ISPs for large-scale NAT deployments
192.0.2.0/24 TEST-NET-1 for documentation
Safe to use in examples and documentation
198.18.0.0/15 Network device benchmarking
Reserved for network performance testing
255.255.255.255 Limited broadcast address
Sends to all hosts on local network
Private IP addresses cannot be routed on the public internet. When devices with private IPs need internet access, Network Address Translation (NAT) is used to translate private addresses to public addresses.
2001:0db8:85a3:0000:0000:8a2e:0370:7334 8 groups of 4 hexadecimal digits each, separated by colons (128 bits total)
2001:0db8:0000:0042 2001:db8:0:42 Leading zeros in each group can be omitted
2001:db8:0:0:0:0:0:1 2001:db8::1 Consecutive zero groups replaced with "::"
2001::db8::1 2001:0:0:db8:0:0:0:1 Only one "::" compression allowed
::ffff:192.168.1.1 ::192.168.1.1 Last 32 bits can be IPv4 notation
2000::/3 Routable on the global internet
Example: 2001:db8:85a3::8a2e:370:7334
fe80::/10 Valid only on local network segment
Example: fe80::1%eth0
fc00::/7 Private addresses for local use
Example: fd12:3456:789a::1
::1/128 Local host (like 127.0.0.1)
Example: ::1
ff00::/8 One-to-many communication
Example: ff02::1 (all nodes)
Same as unicast Delivered to nearest node
Example: 2001:db8::1 (anycast)
::/128 All zeros address
Example: :: (like 0.0.0.0)
::ffff:0:0/96 IPv4 addresses in IPv6 format
Example: ::ffff:192.168.1.1
2001:db8::/32 First 32 bits identify the network
2001:db8:1::/48 Bits 33-48 for subnet identification
2001:db8:1::1/64 Last 64 bits identify the interface
Most IPv6 networks use /64 prefixes for end networks, providing 2^64 addresses per subnet. This allows for easy auto-configuration and plenty of address space.
192.168.1.1 Class C Private Common home router address
10.0.0.1 Class A Private Enterprise network gateway
172.16.0.1 Class B Private Medium-sized network
8.8.8.8 Class A Public Google DNS server
127.0.0.1 Loopback Local host address
0.0.0.0 Special Default route/unspecified
192.168.1.256 Octet > 255 Last octet exceeds maximum value
192.168.01.1 Leading zeros Leading zeros not allowed in IPv4
192.168.1 Missing octets IPv4 requires exactly 4 octets
192.168.1.1.1 Too many octets IPv4 cannot have more than 4 octets
192.168.1.a Invalid characters IPv4 octets must be numeric
2001:db8::1 Global Unicast Documentation prefix (RFC 3849)
fe80::1 Link-Local Local network segment only
::1 Loopback IPv6 localhost address
2001:4860:4860::8888 Global Unicast Google DNS IPv6 server
fc00::1 Unique Local Private IPv6 address
::ffff:192.168.1.1 IPv4-mapped IPv4 address in IPv6 format
2001::db8::1 Multiple "::" Only one "::" compression allowed
2001:db8::gggg Invalid hex Only 0-9, a-f, A-F allowed
2001:12345::1 Group too long Groups limited to 4 hex digits
2001:db8:1:2:3:4:5:6:7 Too many groups IPv6 limited to 8 groups maximum
2001:db8:::1 Triple colon Invalid compression syntax
Octet out of range (0-255)
❌ Example: 192.168.1.256
Leading zeros not allowed
❌ Example: 192.168.01.1
Wrong number of octets
❌ Example: 192.168.1 or 192.168.1.1.1
Multiple "::" compressions
❌ Example: 2001::db8::1
Invalid hexadecimal characters
❌ Example: 2001:db8::gggg
Groups longer than 4 characters
❌ Example: 2001:12345::1