About OpenSER

Please note that OpenSER no longer exists. It was forked into two projects, Kamailio and OpenSIPS. The two projects are currently very similar, given that they are built on the same code base, however the two projects have differing philosophies and goals (hence the fork).

Source of documentation. Please be advised that OpenSER was originally renamed to Kamailio while maintaining all documentation. However the domain now points to OpenSIPS. To secure a proper source of information, the original links to pages now point to the Kamailio domain.

SourceForge Project. The source code tree of OpenSER SIP server application is still hosted by under the old name, the project: SVN repository is used and managed by Kamailio project.

OpenSER was an open source GPL project that aimed to develop a robust and scalable SIP server. It was spawned from FhG FOKUS SIP Express Router (SER) by two core developers and one main contributor of SER, and it promoted a development strategy open for contributions. From project's website About OpenSER.

OpenSER Headlines

  • Monday, November 24, 2008, OpenSER version 1.3.4 was released. The announcement is here.

  • Wednesday, September 27, 2008, OpenSER version 1.3.3 was released. The announcement is here.

  • Thursday, August 7, 2008. A new major release under the new name: Kamailio 1.4.0 is out. It includes lot of improvements in terms of performance and new features. See release notes...

  • Thursday, June 05, 2008, the 2008 edition of OpenSER Advanced Programming Course will take place in Bucharest, Romania between 11th and 14th of August. Registration is free for everybody.

  • Thursday, May 15, 2008, OpenSER version 1.3.2 was released. The announcement is here.

  • Tuesday, March, 2008, OpenSER version 1.3.1 was released. The announcement is here.

  • Tuesday, February 19, 2008, the second OpenSER Summit edition takes place in San Jose on 17th of March 2008 during VoN Spring. Registration is open and free on the project web site.

  • Tuesday, February 13, 2008, first edition of OpenSER Pavilion is set to take place in San Jose between 18th and 19th of March 2008, in the VoN Spring expo area. Read more about this unique event on the project web site.

Headlines Archive

OpenSER Events

Events around the world where you can meet OpenSER folks or OpenSER has dedicated sessions or talks.


Events Archive

OpenSER Capabilities

New features in OpenSER v1.3.0

New features in OpenSER v1.2.0

New features in OpenSER v1.1.0

  • NAPTR support - more DNS-related requirements from RFC3263 are in

  • statistics - lot of internals indicators can be displayed to get a proper overview of OpenSER runtime status
  • many improvements in TCP/TLS
  • basic dialog support - new module features active call listing during runtime
  • possibility to use many more database backends via new unixodbc module
  • some of the legal interception requirements can be achieved by newly introduced siptrace module
  • deployments of the distributed VoIP platform is easily possible using cacheless user location and PATH extensions
  • OSP module for secure peering
  • full list of v1.1.0 news here

New features in OpenSER v1.0.0

  • consolidated SIP server features: SIP registrar, SIP location server, SIP proxy, SIP redirect server, SIP router and SIP application server
  • TLS support - OpenSER is the first free SIP server with integrated TLS support. This enables high secure VoIP communications.
  • easier scripting - new commands as return(x) (returns from current route with code x) and exit (complete script termination), 'switch' statements to handle returned values.
  • easier maintenance of multiple OpenSER instances - config parameter 'mpath' to specify the base directory for modules
  • pseudo-variables support
    • xlog can print any pseudo-variable
    • avpops/avp_printf() - printf-like function to print pseudo-variables in an avp
    • textops/subst(),subst_uri() and subst_user() - have support for pseudo-variables in replacement string
  • flexible accounting - any header or avp can be stored in accounting database
  • proper serial/parallel forking handling in TM
  • alias_db module - direct database user aliases
  • uac_redirect module - handling of redirect replies (3xx) on server
  • more dialog support and better replication and NAT traversal handling
  • read more here for v1.0.0, here for v0.9.x
  • modules' documentation is updated
  • OpenSER Core Cookbook is available at

Basic features of OpenSER

  • SIP proxy/registrar/redirect server (RFC3261, RFC3263)
  • UDP/TCP/TLS support
  • transactional stateful proxy
  • modular architecture
  • programmable configuration file
  • ENUM support
  • Call Processing Language (CPL)
  • gateway to sms or xmpp
  • authentication, authorization and accounting via Radius or database
  • NAT traversal system
  • least cost routing
  • multiple database backends: MySQL, Postgres or flat files




Documentations about OpenSER


Other Resources

Resources about OpenSER

OpenSER Modules


Modules In OpenSER 1.0.0

  • acc - accounting to syslog, database, diameter or radius
  • alias_db - user aliases managed directly in DB (no memory cache)
  • auth- basic authentication functionality
  • auth_db - authentication using database
  • auth_diameter - authentication and authorization using diameter server
  • auth_radius - authentication using RADIUS server
  • avp_radius - loading AVPs from RADIUS server
  • avpops - AVP and pseudo-variables operations
  • cpl-c - call processing language (CPL) support
  • dbtext - small database driver for text files
  • dispatcher - load balancing and dispatching
  • diversion - IETF diversion draft implementation
  • domain - multi-domain operations
  • enum - ENUM functionality and support
  • exec - allow execution of external scripts
  • flatstore - support for writing accounting data to flat files
  • gflags - global flags
  • group - group membership checking
  • group_radius - group membership checking using RADIUS server
  • jabber - gateway to jabber/xmpp
  • lcr - least cost routing
  • mangler - message mangling from config file
  • maxfwd - max forward processing
  • mediaproxy - nat traversal using media proxy
  • msilo - offline message storage
  • mysql - connector to mysql databse server
  • nathelper - nat traversal using rtpproxy
  • options - processing of option requests
  • osp - Multi-Lateral Peering using OSP protocol
  • pa - presence agent
  • pdt- prefix-domain translation
  • permissions - set permissions for users and peers
  • pike - flood detection
  • postgres - connector to postgres database server
  • registrar - user registration processing
  • rr - record routing processing
  • sl - stateless reply generation
  • sms - gateway to sms
  • speeddial - short dialing on server
  • textops - text operations over the SIP message
  • tm - transactional module
  • uac - basic uac functionality for openser server
  • uac_redirect - server side handling of redirect replies (3xx)
  • uri - operations for SIP URIs
  • uri_db - operations for SIP URIs using database server
  • uri_radius - operations for SIP URIs using RADIUS server
  • usrloc - user location service
  • xlog - formatted message printing, useful for debugging


New Modules In OpenSER 1.1.0 (old stable)

  • dialog - dialog support (call stateful) in SIP server
  • path - PATH support in SIP server
  • siptrace - trace SIP messages, useful for legal interception requirements
  • statistics - support for statistics variables in configuration script
  • unixodbc - database connection driver using unixodbc


New Modules In OpenSER 1.2.0 (old stable)

  • imc - Instant Messaging Conferencing
  • domainpolicy - policy management for connecting federations
  • mi_fifo - FIFO file transport for new management interface (MI)
  • mi_xmlrpc - XMLRPC transport for new management interface (MI)
  • perl - Perl scripting integration — allow embedding of Perl functions execution
  • presence - SIMPLE presence server implementation
  • pua - SIMPLE presence user agent client common API
  • pua_mi - SIMPLE presence user agent client implementation for new management interface (MI)
  • pua_usrloc - SIMPLE presence user agent client common implementation for user location records
  • seas - SIP Express Application Server module - enables communication with WeSIP - the Java SIP Servlet application server
  • snmpstats - Simple Network Management Interface (SNMP) to OpenSER statistics
  • sst - SIP session timer support
  • xmpp - on-the-fly SIP-XMPP (google talk) instant messaging gateway


New Modules In OpenSER 1.3.0 (latest stable)


New Modules In OpenSER 1.4.0 (development version)

Deploying OpenSER

OpenSER and Asterisk

OpenSER and NAT


OpenSER accounting, rating and tracing

OpenSER and XCAP presence policy

  • OpenXCAP - An Open Source XCAP server implementation

Monitoring OpenSER

OpenSER and Web Interfaces

OpenSER Configuration Auto-generator

Practical Examples


OpenSER is know to work on
  • most of Linux flavours (OS used for development is mainly Debian)
  • 64b Linux flavours
  • SUN/Solaris
  • FreeBSD
  • OpenBSD
  • NetBSD


See also

Created by: gst, Last modification: Sun 15 of Feb, 2009 (01:39 UTC) by admin
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