IPv4
Special-use addresses
The Internet Engineering Task Force (IETF) and the Internet Assigned Numbers Authority (IANA) have restricted from general use various reserved IP addresses for special purposes.

IPv4

Section Title: Special-use addresses
Table Section Text: The Internet Engineering Task Force (IETF) and the Internet Assigned Numbers Authority (IANA) have restricted from general use various reserved IP addresses for special purposes.

Address block	Address range	Number of addresses	Scope	Description

0.0.0.0/8	0.0.0.0–0.255.255.255	16777216	Software	Current network (only valid as source address).

10.0.0.0/8	10.0.0.0–10.255.255.255	16777216	Private network	Used for local communications within a private network.

100.64.0.0/10	100.64.0.0–100.127.255.255	4194304	Private network	Shared address space for communications between a service provider and its subscribers when using a carrier-grade NAT.

127.0.0.0/8	127.0.0.0–127.255.255.255	16777216	Host	Used for loopback addresses to the local host.

169.254.0.0/16	169.254.0.0–169.254.255.255	65536	Subnet	Used for link-local addresses between two hosts on a single link when no IP address is otherwise specified, such as would have normally been retrieved from a DHCP server.

172.16.0.0/12	172.16.0.0–172.31.255.255	1048576	Private network	Used for local communications within a private network.

192.0.0.0/24	192.0.0.0–192.0.0.255	256	Private network	IETF Protocol Assignments.

192.0.2.0/24	192.0.2.0–192.0.2.255	256	Documentation	Assigned as TEST-NET-1, documentation and examples.

192.88.99.0/24	192.88.99.0–192.88.99.255	256	Internet	Reserved. Formerly used for IPv6 to IPv4 relay (included IPv6 address block 2002::/16).

192.168.0.0/16	192.168.0.0–192.168.255.255	65536	Private network	Used for local communications within a private network.

198.18.0.0/15	198.18.0.0–198.19.255.255	131072	Private network	Used for benchmark testing of inter-network communications between two separate subnets.

198.51.100.0/24	198.51.100.0–198.51.100.255	256	Documentation	Assigned as TEST-NET-2, documentation and examples.

203.0.113.0/24	203.0.113.0–203.0.113.255	256	Documentation	Assigned as TEST-NET-3, documentation and examples.

224.0.0.0/4	224.0.0.0–239.255.255.255	268435456	Internet	In use for IP multicast. (Former Class D network).

240.0.0.0/4	240.0.0.0–255.255.255.254	268435456	Internet	Reserved for future use. (Former Class E network).

255.255.255.255/32	255.255.255.255	1	Subnet	Reserved for the "limited broadcast" destination address.

Sentence(s)

The network 127.0.0.0/8 is used for loopbacks.

final_sentence: The network 127.0.0.0/8 is used for loopbacks.