Registry included below
The IETF has reserved the address block of 192.0.0.0/24 for use for special purposes relating to protocol assignments. This registry contains the current assignments made by the IETF from this address block. Address prefixes listed in the Special-Purpose Address Registry are not guaranteed routability in any particular local or global context. The IPv4 and IPv6 Special-Purpose Address Registries maintain the following information regarding each entry: o Address Block - A block of IPv4 or IPv6 addresses that has been registered for a special purpose. o Name - A descriptive name for the special-purpose address block. o RFC - The RFC through which the special-purpose address block was requested. o Allocation Date - The date upon which the special-purpose address block was allocated. o Termination Date - The date upon which the allocation is to be terminated. This field is applicable for limited-use allocations only. o Source - A boolean value indicating whether an address from the allocated special-purpose address block is valid when used as the source address of an IP datagram that transits two devices. o Destination - A boolean value indicating whether an address from the allocated special-purpose address block is valid when used as the destination address of an IP datagram that transits two devices. o Forwardable - A boolean value indicating whether a router may forward an IP datagram whose destination address is drawn from the allocated special-purpose address block between external interfaces. o Global - A boolean value indicating whether an IP datagram whose destination address is drawn from the allocated special-purpose address block is forwardable beyond a specified administrative domain. o Reserved-by-Protocol - A boolean value indicating whether the special-purpose address block is reserved by IP, itself. This value is "TRUE" if the RFC that created the special-purpose address block requires all compliant IP implementations to behave in a special way when processing packets either to or from addresses contained by the address block. If the value of "Destination" is FALSE, the values of "Forwardable" and "Global" must also be false.
|Address Block||Name||RFC||Allocation Date||Termination Date||Source||Destination||Forwardable||Global||Reserved-by-Protocol|
|0.0.0.0/8||"This host on this network"||[RFC1122], section 220.127.116.11||1981-09||N/A||True||False||False||False||True|
|100.64.0.0/10||Shared Address Space||[RFC6598]||2012-04||N/A||True||True||True||False||False|
|127.0.0.0/8||Loopback||[RFC1122], section 18.104.22.168||1981-09||N/A||False||False||False||False||True|
|192.0.0.0/24||IETF Protocol Assignments||[RFC6890], section 2.1||2010-01||N/A||False||False||False||False||False|
|192.0.0.0/29||IPv4 Service Continuity Prefix||[RFC7335]||2011-06||N/A||True||True||True||False||False|
|22.214.171.124/32||IPv4 dummy address||[RFC7600]||2015-03||N/A||True||False||False||False||False|
|126.96.36.199/32||Port Control Protocol Anycast||[RFC7723]||2015-10||N/A||True||True||True||True||False|
|188.8.131.52/32||Traversal Using Relays around NAT Anycast||[RFC-ietf-tram-turn-server-discovery-12]||2017-02||N/A||True||True||True||True||False|
|192.0.0.170/32, 192.0.0.171/32||NAT64/DNS64 Discovery||[RFC7050], section 2.2||2013-02||N/A||False||False||False||False||True|
|184.108.40.206/24||Deprecated (6to4 Relay Anycast)||[RFC7526]||2001-06||2015-03|
|220.127.116.11/24||Direct Delegation AS112 Service||[RFC7534]||1996-01||N/A||True||True||True||True||False|
|240.0.0.0/4||Reserved||[RFC1112], section 4||1989-08||N/A||False||False||False||False||True|
|255.255.255.255/32||Limited Broadcast||[RFC919], section 7||1984-10||N/A||False||True||False||False||False|
Several protocols have been granted exceptions to this rule. For examples, see [RFC-ietf-mpls-rfc4379bis-09] and [RFC5884].
Not useable unless by virtue of a more specific reservation.