[SR-Users] Kamailio behind NAT - best practice

Hi! Up to now I could avoid Kamailio setups with Kamailio behind NAt. But this time I have to deal with it. That's why I want to ask what others did as best practice. The scenario is: Asterisk 1----\ Kamailio+RTPPROXY \ |10.10.0.2 Asterisk n------\ | --------|------------- FW --SIP-trunk--- ITSP Freeswitch 1----/ 10.10.0.1 public-IP / Freeswitch n--/ 10.10.0.x Kamailio and rtpproxy have a private IP. Internal communication uses private IPs, external communication uses a public IP which is NATed 1:1 to Kamailio's IP address. No registrations, just forwarding of messages. Using the global "advertised_address" setting with the public IP does not work, as there is also internal communication. Using set_advertised_address() is also cumbersome. So it seems, the easiest solution would be to use 2 sockets on Kamailio, e.g. port 5050 and port 5060. Then I could use the listen with dedicated advertised addresses: listen=udp:10.10.0.2:5050 listen=udp:10.10.0.2:5060 advertise pu.bl.ic.ip:5060 If I understand it correctly, this should solve all issues with Record-Routing and Via-headers. For RTP-Proxy it seems necessary to detect the direction of each message and set the IP address in rtpproxy_manage("","ip.add.re.ss") manually. Thus, it seems straight forward - or do I miss something? Any comments and practical experience? Thanks Klaus