An Extension to the Session Initiation Protocol for Symmetric Response Routing
RFC 3581, “An Extension to the Session Initiation Protocol for Symmetric Response Routing”, is a Proposed Standard document published in August 2003 by J. Rosenberg, H. Schulzrinne. The canonical text is published by the RFC Editor.
Abstract
The Session Initiation Protocol (SIP) operates over UDP and TCP, among others. When used with UDP, responses to requests are returned to the source address the request came from, and to the port written into the topmost Via header field value of the request. This behavior is not desirable in many cases, most notably, when the client is behind a Network Address Translator (NAT). This extension defines a new parameter for the Via header field, called "rport", that allows a client to request that the server send the response back to the source IP address and port from which the request originated. [STANDARDS-TRACK]
What “Proposed Standard” means
An entry-level standards-track specification: stable, peer-reviewed and a solid basis for implementation, though it may still evolve before becoming an Internet Standard.
The canonical text of RFC 3581 is hosted at rfc-editor.org. Available in TXT,HTML.
- RFC 3580 IEEE 802.1X Remote Authentication Dial In User Service Usage Guidelines
- RFC 3582 Goals for IPv6 Site-Multihoming Architectures
- RFC 3579 RADIUS Support For Extensible Authentication Protocol
- RFC 3583 Requirements of a Quality of Service Solution for Mobile IP
- RFC 3584 Coexistence between Version 1, Version 2, and Version 3 of the Internet-standard Network Management Framework
- RFC 3578 Mapping of Integrated Services Digital Network User Part Overlap Signalling to the Session Initiation Protocol
- RFC 3585 IPsec Configuration Policy Information Model
- RFC 3577 Introduction to the Remote Monitoring Family of MIB Modules