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IPv6 Address Type Classifier

Identify architectural address types.

IPv6 Address Type Classifier: inputs and results

Enter an IP address, CIDR prefix, or range. Then check its first and last address below.

Quick presets:

Calculated Boundaries & ParametersReady

Network Address192.168.1.0
Broadcast Address192.168.1.255
First Usable Host192.168.1.1
Last Usable Host192.168.1.254
Subnet Mask255.255.255.0
Wildcard Mask0.0.0.255
Total Addresses256
Usable Host Range254

Key Capabilities

  • •100% Client-Side: Zero telemetry or server latency.
  • •RFC Compliant: Exact 32-bit and 128-bit integer precision.
  • •Quick Copy: Instant access to CIDR, mask, and range bounds.
  • •Cross-Platform: Works on desktop, tablet, and mobile browsers.
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How IPv6 Address Type Classifier Works?

The IPv6 Address Type Classifier works by matching the address against the IPv6 address architecture prefixes from RFC 4291 and the IANA special-purpose registry, then returning the most specific type.

  1. Enter an IPv6 address

    Type an address such as fd12:3456:789a:1::1.

  2. Expand to 128 bits

    The classifier expands the address so prefix tests run on exact bits.

  3. Test each type prefix

    The address is checked against prefixes such as fe80::/10, fc00::/7, and ff00::/8.

  4. Return the type and scope

    The classifier reports the type (Unique Local), the defining RFC, and the scope.

IPv6 Address Type Classifier Formula

The IPv6 Address Type Classifier formula is Type = the type prefix with the longest length p where (IP AND Mask(p)) = Type Prefix.

Prefix test

(IP AND Mask(p)) = T

Runs for every type prefix.

Most specific wins

max(p)

2001:db8::/32 beats 2000::/3.

Multicast scope

Scope = 4th hex digit of ff0X

ff02 → link-local, ff05 → site-local, ff0e → global.

Worked example: fd12:3456:789a:1::1

fc00::/7 → first 7 bits 1111110
fd = 11111101 → first 7 bits 1111110 ✓
Type  = Unique Local Address (ULA)
RFC   = RFC 4193
Scope = Global prefix, not routed on the internet

IPv6 Address Type Classifier Conversion Table

The IPv6 Address Type Classifier conversion table lists 12 IPv6 address types with the prefix, defining RFC, and a sample address.

PrefixTypeRFCSample Address
::/128UnspecifiedRFC 4291::
::1/128LoopbackRFC 4291::1
::ffff:0:0/96IPv4-mappedRFC 4291::ffff:192.0.2.1
64:ff9b::/96NAT64 well-known prefixRFC 605264:ff9b::c000:201
100::/64Discard-onlyRFC 6666100::1
2000::/3Global unicastRFC 42912606:4700::1111
2001::/32TeredoRFC 43802001:0:4136:e378::1
2001:db8::/32DocumentationRFC 38492001:db8::1
2002::/166to4RFC 30562002:c000:201::1
fc00::/7Unique local (ULA)RFC 4193fd12:3456:789a:1::1
fe80::/10Link-local unicastRFC 4291fe80::1
ff00::/8MulticastRFC 4291ff02::1

What is IPv6 Address Type Classifier?

The IPv6 Address Type Classifier is a tool that identifies the architectural type of an IPv6 address, such as global unicast, unique local, link-local, or multicast.

IPv6 encodes the address type in the leading bits. Every interface carries at least 2 types at once: a link-local fe80:: address and 1 or more global or unique local addresses. The classifier tells them apart instantly.

The classifier catches special blocks that look like normal addresses, such as 2001:db8::/32 for documentation and 2001::/32 for Teredo tunneling.

What are the uses of IPv6 Address Type Classifier?

There are 4 main uses of the IPv6 Address Type Classifier, including troubleshooting, filtering, and log enrichment.

  • Troubleshooting connectivity

    A host with only fe80:: addresses has no global address, which explains failed internet access.

  • Building IPv6 edge filters

    Edge filters drop documentation, ULA, and other non-global sources.

  • Enriching security logs

    Log pipelines tag each address with its type for faster triage.

  • Teaching IPv6 architecture

    Students map prefixes to scopes with live examples.