General Questions

  • How do I provision a new identity?
    You can always use the FHoSS web interface running accesible http://localhost:8080 on the FHoSS machine (this web-interface is part of the HSS, so you need to run the HSS in order to access it).
    For automating this process, you can also use the script found in the ser_ims/cfg/. Look inside for usage instructions.
  • Can I contribute with another IMS component that I am working on?
    As long as it’s covered by our topic, you are most welcomed. Just let us know and we will import it in the SVN.


  • I tried the SVN URLs on berliOS but I get an error.
    berliOS uses a template for indicating the SVN URLs. As we have more than 1 sub-project, please use the links indicated here.
  • I want to commit something, but I don’t have right access.
    In order to keep a high quality for the code, only a limited number of maintainers have modification permissions. Each is responsible for checking if new patches work properly and for the administration of the sub-projects. Please post your patches to the mailing-lists and they will be checked and applied. If you are an active contributor and you demonstrate that your patches can be trusted, we will add you as a project maintainer.
  • OK, but what if I want to make a big change and would require a branch?
    Then you will get this access sooner. You will just have to convince one of the maintainers that your branch makes sense. While working on branches you can be more relaxed regarding commits as you don’t have to make sure each time that your modifications do not break something.

Call Session Control Functions

  • I get an error that “setkey” is not found when starting the P-CSCF. How do I fix it?
    Install the ipsec-tools. “setkey” is included there and it is used to set-up the IPSec Security Associations. Also, don’t forget to check if you have IPSec AH and ESP compiled in your kernel.
  • How do I enable the RTP Proxy?
    Download and install RTPProxy. You can get it from Then start it with the following command line:
    rtpproxy -l -s udp: -f
    Edit the pcscf.cfg and enable the RTPProxy:
    modparam("pcscf","rtpproxy_enable", 1)
  • How can I enable persistency support for my setup ?
    To enable persistency support, just take a look at the pcscf.cfg and scscf.cfg file and there you can find the examples for the new persistency settings in conveninently commented blocks. To enable saving to files use:
  • Do I really need a DNS server? Won’t “/etc/hosts” work?
    You really need a DNS server. For example the P-CSCF will do a NAPTR/SRV query to find the I-CSCF and only a true DNS server will be able to solve this. If you need help with that, please read this.

Home Subscriber Server

  • Can I compile FHoSS without connectivity to Internet?
    The usual problem that occurs when the additional resources are generated, through ant gen, without a current Intenet connection is: Error reading import file '': No route to host. This occurs because the source generator tries to import the specified file from the remote address. The solution is:

    1. Download the xml.xsd from here: xml.xsd and copy it on your machine, for example in xsd/ folder of FHoSS
    2. Edit the file xsd/ZhDataType.xsd and change the path “” to your local path; for example “file:///opt/OpenIMSCore/FHoSS/xsd/xml.xsd”
      E.g. Original file:
      <xs:import namespace="" schemaLocation=""/>
      Modified file:
      <xs:import namespace="" schemaLocation="file:///opt/OpenIMSCore/FHoSS/xsd/xml.xsd"/>
    3. Run again ant gen and now it will work.

SIP-to-IMS Gateway

  • The SIP-to-IMS Gateway is obsolete and was removed from the project. The Open IMS Core supports MD5 authentication without it. See the Installation-Annex Bfor information on how to use SIP clients with the Open IMS Core.

IMS and SIP User Endpoints

  • Is there a free IMS Client?
  • Then how can one else can I test the core?
    The Open IMS Core has support for MD5 authentication. Also, you can use SIPp, which has support even for AKA and media
  • So how do you get a SIP client registered?Some steps are necessary in order to do that:
  • first provision the users (or use the default sip:alice@open-ims.test or sip:bob@open-ims.test). Make sure than in the HSS provisioning interface in the private identity configuration, you allow the use of Digest-MD5 for the respective users.
  • Then you have two options for the S-CSCF to trigger an MD5 authentication
    1. Modify the client to send a parameter “algorithm=MD5” in the Authorization header in the first unauthorized REGISTER.
    2. Or modify the scscf.cfg and enable the MD5 authorization as the default authentication method instead of AKAv1-MD5.
  • Next just make sure that the client is using the P-CSCF address ( by default) as strict outbound proxy and the REGISTER Request-URI is “sip:open-ims.test” (or your own domain name) and not “” as many SIP clients fail here.