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192.0.0.0/24

192.0.0.0/24 is reserved by the IETF for protocol assignments, not for ordinary hosts.

Last updated 2 Nov 2026 from the IANA IPv4 Special-Purpose Address Registry

Short answer

192.0.0.0/24 is reserved by the IETF for protocol assignments, not for ordinary hosts.

Block192.0.0.0/24
First – last192.0.0.0 – 192.0.0.255
Size256 addresses
Name in the registryIETF Protocol Assignments
Defined inRFC 6890, Section 2.1
Allocated2010-01
Valid as source / destinationFalse / False
ForwardableFalse
Globally reachableFalse

What it means

RFC 6890 sets aside 192.0.0.0/24 for specific protocol uses defined in other RFCs (for example, parts of it are used by DS-Lite and NAT64 mechanisms). It is not handed out to customers.

If you see one of these addresses in a log it usually comes from your provider’s transition technology, not from a remote site.

Want the address websites actually see for you? Open the Truth Check.

Sources

  1. IANA IPv4 Special-Purpose Address Registry (CC0) · checked 2 Nov 2026
  2. RFC 6890