Internet Engineering Task Force (IETF) M. Stiemerling
Request for Comments: 5973 NEC
Category: Experimental H. Tschofenig
ISSN: 2070-1721 Nokia Siemens Networks
C. Aoun
Consultant
E. Davies
Folly Consulting
October 2010
NAT/Firewall NSIS Signaling Layer Protocol (NSLP)
Abstract
This memo defines the NSIS Signaling Layer Protocol (NSLP) for
Network Address Translators (NATs) and firewalls. This NSLP allows
hosts to signal on the data path for NATs and firewalls to be
configured according to the needs of the application data flows. For
instance, it enables hosts behind NATs to obtain a publicly reachable
address and hosts behind firewalls to receive data traffic. The
overall architecture is given by the framework and requirements
defined by the Next Steps in Signaling (NSIS) working group. The
network scenarios, the protocol itself, and examples for path-coupled
signaling are given in this memo.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for examination, experimental implementation, and
evaluation.
This document defines an Experimental Protocol for the Internet
community. 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
http://www.rfc-editor.org/info/rfc5973.
Stiemerling, et al. Experimental [Page 1]
RFC 5973 NAT/FW NSIS NSLP October 2010
Copyright Notice
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Contributions published or made publicly available before November
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Without obtaining an adequate license from the person(s) controlling
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it for publication as an RFC or to translate it into languages other
than English.
Stiemerling, et al. Experimental [Page 2]
RFC 5973 NAT/FW NSIS NSLP October 2010
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1. Scope and Background . . . . . . . . . . . . . . . . . . . 5
1.2. Terminology and Abbreviations . . . . . . . . . . . . . . 8
1.3. Notes on the Experimental Status . . . . . . . . . . . . . 10
1.4. Middleboxes . . . . . . . . . . . . . . . . . . . . . . . 10
1.5. General Scenario for NATFW Traversal . . . . . . . . . . . 11
2. Network Deployment Scenarios Using the NATFW NSLP . . . . . . 13
2.1. Firewall Traversal . . . . . . . . . . . . . . . . . . . . 13
2.2. NAT with Two Private Networks . . . . . . . . . . . . . . 14
2.3. NAT with Private Network on Sender Side . . . . . . . . . 15
2.4. NAT with Private Network on Receiver Side Scenario . . . . 15
2.5. Both End Hosts behind Twice-NATs . . . . . . . . . . . . . 16
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