behave WG W. Meng Internet-Draft ZTE Corporation Intended status: Standards Track July 15, 2013 Expires: January 16, 2014 Network Address Port Group Translator draft-meng-behave-napgt-01 Abstract Currently, if an internal server and hosts are behind NAT, they cannot share a global IP address except adding lots of static NAPT rule configuration. Because if a server wants to provide a service by constant port(i.e. HTTP and FTP) , the destination port of packet sent by an external client should not be changed when it crosses NAT. This document specifies a new method to assign NAPT global address and port, aiming to solve the problem that internal servers and hosts cannot share less global IP addresses. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on January 16, 2014. Copyright Notice Copyright (c) 2013 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 Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must Meng Expires January 16, 2014 [Page 1] Internet-Draft Network Address Port Group Translator July 2013 include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Convention and Terminology . . . . . . . . . . . . . . . . . 3 3. Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Configuration . . . . . . . . . . . . . . . . . . . . . . . . 3 5. Mapping Item . . . . . . . . . . . . . . . . . . . . . . . . 3 6. Security Considerations . . . . . . . . . . . . . . . . . . . 4 7. Normative References . . . . . . . . . . . . . . . . . . . . 4 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction With the depletion of IPv4 addresses, many operators have begun to deploy NAPT in their network. However, the use of NAPT has many shortcomings. For example, a server is placed in an internal network, this may happen when an external client attempts to access a server in the internal network through HTTP. Dynamic NAPT cannot be used for translation except for NAT, because the translation MUST keep the consistency of the internal port and external port (PORT:80 should not be changed). This may be causing a public IP address being occupied to a server, but not for other users to access, resulting in a misuse of resources. It appears that STATIC NAPT is a near-perfect solution to deal with this issue. However, However, if there are a lot of services or servers in the internal network, it may not be useful to configure a huge number of STATIC NAPT rules. This will increase the complexity of configuration without a corresponding increase in functionality. The current existing solution works by changing the configuration due to user complaints. A user does not know whether his/her IP address is global or local. During the use of a global IP address, he/she can access the server placed in his home from external. Until one day, he/she cannot do that because he/she gets a local IP address. He/She is not satisfied and complains to the operator. Operator has to assign global IP address for him/her and still assign local IP address for others. Operator distinguishes him/her from others by embedding tags into the subscriber backend database. Now, through the variant of traditional NAPT translation, we can achieve sharing a global IP address among a server and hosts placed in the same internal network. It is called NAPGT (Network Address Port Group Translator). Meng Expires January 16, 2014 [Page 2] Internet-Draft Network Address Port Group Translator July 2013 2. Convention and Terminology 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 [RFC2119]. 3. Scenarios There can be a typical scenario if NAT is involved. In this scenario, a server and several hosts are behind NAT. NAT has only a global IP address. NAT needs to let client access to server without affecting any hosts accessing to the internet. Address Pool: {202.1.1.1 } +----------+ +-----+ +--------+ +--------+ | | | | |HTTP/FTP| | Client |----+ Internet + ----+ NAT +----+ Server + +--------+ | | | | | | | +----------+ +-----+ | +--------+ | +--------+ |--+ host + | +--------+ | +--------+ |--+ host + | +--------+ | +--------+ |--+ host + +--------+ Figure 1: Server and Hosts Behind NAT 4. Configuration The NAPGT needs to be configured in a NAT device. Port-ranges MUST be specified in NAT pool, such as '1-1024','7000-7100'. It means that a collection of ports MUST be utilized for binding. The rest of ports can be assigned to hosts. Static or dynamic rules MUST be configured for server. Rules for hosts has no special requirement. 5. Mapping Item Meng Expires January 16, 2014 [Page 3] Internet-Draft Network Address Port Group Translator July 2013 To achieve client accessing server behind NAT by HTTP or FTP, mapping item MUST be generated in advance. NAT(config)#show nat translations all =============================================================================== Protocol Type Local Add:Port global Add:Port Destination Add:Port =============================================================================== --- NAPGT 192.168.0.1:<1-1024> 202.1.1.1:<1-1024> 211.1.1.1:* ------------------------------------------------------------------------------- UDP STATIC 192.168.0.2:1024 202.1.1.1:1025 222.1.1.1 ------------------------------------------------------------------------------- TCP DYNAMIC 192.168.0.3:2565 202.1.1.1:1030 --- ------------------------------------------------------------------------------- Figure 2: Mapping Item in NAT(Example) 6. Security Considerations To be added later on as-needed basis. 7. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Author's Address Wei Meng ZTE Corporation No.50 Software Avenue, Yuhuatai District Nanjing China Email: meng.wei2@zte.com.cn, vally.meng@gmail.com Meng Expires January 16, 2014 [Page 4]