Blocks that have a special meaning, from the IANA registries, fetched on 14 November 2026.
IPv4
Block
Name
RFC
Forwardable
Globally reachable
0.0.0.0/8
This network
RFC 791, Section 3.2
False
False
0.0.0.0/32
This host on this network
RFC 1122, Section 3.2.1.3
False
False
10.0.0.0/8
Private-Use
RFC 1918
True
False
100.64.0.0/10
Shared Address Space
RFC 6598
True
False
127.0.0.0/8
Loopback
RFC 1122, Section 3.2.1.3
False
False
169.254.0.0/16
Link Local
RFC 3927
False
False
172.16.0.0/12
Private-Use
RFC 1918
True
False
192.0.0.0/24
IETF Protocol Assignments
RFC 6890, Section 2.1
False
False
192.0.0.0/29
IPv4 Service Continuity Prefix
RFC 7335
True
False
192.0.0.8/32
IPv4 dummy address
RFC 7600
False
False
192.0.0.9/32
Port Control Protocol Anycast
RFC 7723
True
True
192.0.0.10/32
Traversal Using Relays around NAT Anycast
RFC 8155
True
True
192.0.0.170/32, 192.0.0.171/32
NAT64/DNS64 Discovery
RFC 8880]; [RFC 7050, Section 2.2
False
False
192.0.2.0/24
Documentation (TEST-NET-1)
RFC 5737
False
False
192.31.196.0/24
AS112-v4
RFC 7535
True
True
192.52.193.0/24
AMT
RFC 7450
True
True
192.88.99.0/24
Deprecated (6to4 Relay Anycast)
RFC 7526
n/a
n/a
192.88.99.2/32
6a44-relay anycast address
RFC 6751
True
False
192.168.0.0/16
Private-Use
RFC 1918
True
False
192.175.48.0/24
Direct Delegation AS112 Service
RFC 7534
True
True
198.18.0.0/15
Benchmarking
RFC 2544
True
False
198.51.100.0/24
Documentation (TEST-NET-2)
RFC 5737
False
False
203.0.113.0/24
Documentation (TEST-NET-3)
RFC 5737
False
False
240.0.0.0/4
Reserved
RFC 1112, Section 4
False
False
255.255.255.255/32
Limited Broadcast
RFC 8190]; [RFC 919, Section 7
False
False
IPv6
Block
Name
RFC
Forwardable
Globally reachable
::1/128
Loopback Address
RFC 4291
False
False
::/128
Unspecified Address
RFC 4291
False
False
::ffff:0:0/96
IPv4-mapped Address
RFC 4291
False
False
64:ff9b::/96
IPv4-IPv6 Translat.
RFC 6052
True
True
64:ff9b:1::/48
IPv4-IPv6 Translat.
RFC 8215
True
False
100::/64
Discard-Only Address Block
RFC 6666
True
False
100:0:0:1::/64
Dummy IPv6 Prefix
RFC 9780
False
False
2001::/23
IETF Protocol Assignments
RFC 2928
False
False
2001::/32
TEREDO
RFC 4380]; [RFC 8190
True
N/A
2001:1::1/128
Port Control Protocol Anycast
RFC 7723
True
True
2001:1::2/128
Traversal Using Relays around NAT Anycast
RFC 8155
True
True
2001:1::3/128
DNS-SD Service Registration Protocol Anycast
RFC 9665
True
True
2001:2::/48
Benchmarking
RFC 5180]; [RFC Errata 1752
True
False
2001:3::/32
AMT
RFC 7450
True
True
2001:4:112::/48
AS112-v6
RFC 7535
True
True
2001:10::/28
Deprecated (previously ORCHID)
RFC 4843
n/a
n/a
2001:20::/28
ORCHIDv2
RFC 7343
True
True
2001:30::/28
Drone Remote ID Protocol Entity Tags (DETs) Prefix
RFC 9374
True
True
2001:db8::/32
Documentation
RFC 3849
False
False
2002::/16
6to4
RFC 3056
True
N/A
2620:4f:8000::/48
Direct Delegation AS112 Service
RFC 7534
True
True
3fff::/20
Documentation
RFC 9637
False
False
5f00::/16
Segment Routing (SRv6) SIDs
RFC 9602
True
False
fc00::/7
Unique-Local
RFC 4193]; [RFC 8190
True
False
fe80::/10
Link-Local Unicast
RFC 4291
False
False
How to use the tables
"Forwardable" says whether a router may pass packets from or to the block beyond its own network, and "Globally reachable" says whether the block is meant to be reachable from the public internet. Blocks marked False for both are internal-only. If an address from one of these blocks shows up as the source of a request from the internet, it is probably forged.
Not in these tables
Multicast ranges (224.0.0.0/4 in IPv4, ff00::/8 in IPv6) are allocated through other registries. The calculators on this site label multicast separately. For private addresses and NAT, see the page on private IP ranges.
This is an independent guide. It is not connected with IANA, the IETF or any network equipment maker. Address and port data come from the IANA registries as fetched on 14 November 2026; RFC texts were read from rfc-editor.org. Check the originals for anything you rely on.
Subnet and Ports