-1- Preamble :

This is a tutorial to configure PSI instant messaging software for voice ( and video ). PSI is an instant messaging  free software which includes voice over IP solution using Jingle RTP protocol. The following configuration is adapted to users who are "mastering" the setup of a DNS name for their local external router interface. The DNS setup is needed  to allow the network localisation of each peer of the coomunication. A method 2 is also available on this web site to avoid the DNS configuration.

-2- Programs and material inventory :

• -a- a jabber server or XMPP server.
• -b- your Internet  interconnection routeur. ( In the following sample we used a zyxel router NBG410W3G model. )
• -c- Your instant messaging PSI software ( Here the PSI free software version 0.13 and above ).

-3- Configurations:

-a- On the jabber server :

You have nothing to do on it ! The server administrator has nothing to to at all. Your existing jabber account should be ok.  If you have any doubt, you can create a free jabber account on our server via this site web dediated to jabber - xmpp. The jabber server is used only for signalisation routing concerning the voice and video features presented in this tutorial. It means that "only" the configuration of your Internet connection and your IM software setup are primordial to let the P2P voice and video be correctly done between your machine and the one of your contact. Voice and video informations DO NOT GO through the jabber server but are exchange between clients.

-b- Your Internet router :

It must be configured to forward incoming UDP port from 8010 to 8013 AND allow your external interface to be resolved into a fixe DNS name. This DNS resolution MUST be the same for client inside AND outside your network.

• UDP 8010 to 8011 is for voice.
• UDP 8012 et 8013 is for video ( not available when this tutorial has been written ) .

Here is a sample for a ZYXEL router / firewall. You have to be logged as administrator on your router and follow this 3 STEPS :

STEP -b1- : go into "ADVANCED / NAT / Port Triggering" page - Here you are going to allow the P2P connections between your internal network and the one of your jabber contact on Internet. ( The WAN1 or WAN2 value represents your router external interface . Adapte this configuration to fit your particular needs. The NBG410W3G model used for this tutorial got 2 external interfaces. ) . It is aslo possible to use the "Port Forwarding" instead of "Port Triggering" if your have only one internal machine on which you what to allow voice and video traffic via PSI.  Here we are using the zyxel Port Triggering function which allow several internal machine to use the service. The Port Triggering function allow to distinguish several machine internaly and let each of them use the port forwarding features.

STEP -b2- : go into " SECURITY / FIREWALL / Rule Summary" - Her we authorize P2P connections, on a firewall point of view, between your internal machines and the ones of your jabber contacts. ( the WAN2 or (WAN1) value corresponds to your external interface router. )

STEP -b3- : go into " ADVANCED / DNS /  DDNS "  - Here you configure how your external interface router is known by a DNS name. This DNS name will be published into your PSI software configuration, we will see that later. Into our sample, we use the ficticious name "MyIPaddress.dyndns.org". To setup a DNS name linked to our dynamique IP we use the DYNDNS free services.

-c- Your Instant Messaging PSI software ( PSI version 0.13 and above ) :

Acces to the windows " Applications " and " Voice Calling " via the Options window :

STEP -c1- : Into " Application " configure the following values :

• Data trasfer base port : 8010
• Data transfer external address : YOUR DYNAMIQUE DNS NAME. ( In our sample : "MyIPaddress.dyndns.org " )

STEP -c2- : Into " Voice Calling " : force your material and replace the default values.

At this step, we suggest you to verify that your computer resolve correctly your external IP according to your DNS name. This is this adress IP which is going to be sent to your jabber contact to allow the voice and video UDP traffic between both machines. The commun eror is to send your INTERNAL IP instead of your Internet routeur EXTERNAL IP. Open a DOS windows and type:

• nslookup
• set query=any
• "Your DNS NAME "

The following drawing is a sample. You MUST obtain the same IP address that the one your get when you go on this web site : www.whatismyipaddress.com

EOF.