RFC 2993 (rfc2993) - Page 1 of 29
Architectural Implications of NAT
Alternative Format: Original Text Document
Network Working Group T. Hain
Request for Comments: 2993 Microsoft
Category: Informational November 2000
Architectural Implications of NAT
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2000). All Rights Reserved.
Abstract
In light of the growing interest in, and deployment of network
address translation (NAT) RFC-1631, this paper will discuss some of
the architectural implications and guidelines for implementations. It
is assumed the reader is familiar with the address translation
concepts presented in RFC-1631.
Table of Contents
1. Introduction................................................... 2
2. Terminology.................................................... 4
3. Scope.......................................................... 6
4. End-to-End Model............................................... 7
5. Advantages of NATs............................................. 8
6. Problems with NATs............................................ 10
7. Illustrations................................................. 13
7.1 Single point of failure...................................... 13
7.2. ALG complexity............................................. 14
7.3. TCP state violations........................................ 15
7.4. Symmetric state management................................. 16
7.5. Need for a globally unique FQDN when advertising public
services................................................... 18
7.6. L2TP tunnels increase frequency of address collisions...... 19
7.7. Centralized data collection system report correlation...... 20
8. IPv6.......................................................... 21
9. Security Considerations....................................... 22
10. Deployment Guidelines........................................ 23
11. Summary...................................................... 24
12. References................................................... 27
Hain Informational