Sunday, October 12, 2008 3:43:16 PM Iñaki Baz Castillo wrote: OpenSer behind a NAT router with dynamic IP? It's really an annoying scenario. Note that when the INVITE/200/(ACK) comes from the LAN 192.168.10.X and goes through OpenSer, you must replace the media IP in the SDP and the IP in "Contact" with the **public** IP of the LAN router, that is a dynamic IP and AFAIK it's not valid to set a domain in the SDP. And when he INVITE/200/(ACK) comes from Internet and goes through OpenSer, you must replace the media IP in the SDP and IP in "Contact" with the eth1 IP of RtpProxy (19.168.10.1). Iñaki I am replacing it for the private ip that I obtain of my router adsl 192.168.1.64, in some examples I read that they replace for the ip it public.. what you try to say is that it replaces the ip that comes from the router for the ip of the lan Also, you need the SIP ports and RtpProxy media ports redirected in the router to the RtpProxy server. that already has it configured in my router ... Anyway, this scenario is not appropiate for a businnes service. you are right, I have a wall of NAT I have open the ports UDP 5060:5065, 10000:20000, 35000:65000 TCP: 5060 Why do you open all these ports? and what do you mean with "open"? don't you mean "redirected"? excuse me, I meant that the ports this redirect to my server PD: A suggestion: Buy an space in a datacenter (a virtual machine could be enough depending on your traffic ammount) and install the OpenSer and RtpProxy decently in a host with public IP. ;) best regards .. rickygm