Internet Engineering Task Force (IETF) J. Arkko
Request for Comments: 5737 Ericsson
Updates: 1166 M. Cotton
Category: Informational L. Vegoda
ISSN: 2070-1721 ICANN
IPv4 Address Blocks Reserved for Documentation
Three IPv4 unicast address blocks are reserved for use in examples in
specifications and other documents. This document describes the use
of these blocks.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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described in the Simplified BSD License.
Arkko, et al. Informational [Page 1]RFC 5737 IPv4 Examples January 20101. Introduction
This document describes three IPv4 address blocks that are provided
for use in documentation. The use of designated address ranges for
documentation and examples reduces the likelihood of conflicts and
confusion arising from the use of addresses assigned for some other
[RFC1166] reserves the first of the three address blocks,
192.0.2.0/24. The other two address blocks have recently been
allocated for this purpose, primarily to ease the writing of examples
involving addresses from multiple networks.
Other documentation ranges have been defined in the IETF, including
the IPv6 documentation prefix [RFC3849] and example domain names
[RFC2606]. Documentation also makes use of the ranges reserved in
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14, [RFC2119].
3. Documentation Address Blocks
The blocks 192.0.2.0/24 (TEST-NET-1), 198.51.100.0/24 (TEST-NET-2),
and 203.0.113.0/24 (TEST-NET-3) are provided for use in
4. Operational Implications
Addresses within the TEST-NET-1, TEST-NET-2, and TEST-NET-3 blocks
SHOULD NOT appear on the public Internet and are used without any
coordination with IANA or an Internet registry [RFC2050]. Network
operators SHOULD add these address blocks to the list of non-
routeable address spaces, and if packet filters are deployed, then
this address block SHOULD be added to packet filters.
These blocks are not for local use, and the filters may be used in
both local and public contexts.
Arkko, et al. Informational [Page 2]RFC 5737 IPv4 Examples January 20105. The Status of 22.214.171.124/16
Note that 126.96.36.199/16 has been used for some examples in the past.
However, this block did not appear in the list of special prefixes in
[RFC3330] or its successors, and the block is therefore not reserved
for any special purpose. The block can be used for regular address
assignments with caution.
6. Security Considerations
This document has no security implications.
7. IANA Considerations