Reserved Protocol
This page provides information on IP Protocol #255. The IP protocol is a permanently reserved value and is not assigned to any specific network protocol. As a result, it has no defined protocol format, standard implementation, or expected use on modern IP networks.
Protocol number 255 marks the final value in the 8-bit range, held back by IANA as a permanently reserved value rather than assigned to any specific protocol.
IP Protocol Details
- Name
- Reserved Protocol
- Abbreviation
- Reserved
- Status
- Reserved
- IANA Number
- 255
- IANA Keyword
- Reserved
- Network Policy
- Drop
- Reference
- Reserved Protocol
IP Protocol Status - Reserved
Protocol number 255 has been reserved since the establishment of the protocol number registry and remains permanently withheld from assignment by design.
IP Protocol Network Policy
IP protocol #255 - Reserved Protocol - is typically dropped by edge routers and firewalls. Advanced threat actors and malware families can use these non-standard IP protocol numbers for lateral movement (east-west communication) inside internal networks.