Hi, My FreeSWITCH machine is located behind the NAT-device. When I receive incoming call, I see 10 secs delay between I picked up handset and voice connection establishing. During these 10s, caller hears long beeps, as same as "ringing" signal. I investigated problem, and found: after recipient pick up handset, FreeSWITCH tried dynamically map two UDP ports for RTP-connections. I use Fios router from Verizon, and I assume, it slowly adding dynamic port mapping. It adds one RTP port per 5s. So, when FS dynamically maps both ports, it loose 10 seconds (5+5). Log follows. I have added static rule into router -- map UDP ports 20000~25000 to FS box. And, in the FS_box, I added into file ./autoload_configs/switch.conf.xml <param name="rtp-start-port" value="20000"/> <param name="rtp-end-port" value="25000"/> But, anyway, FS tries dynamically assign ports for each income call, and lost 10s every time. Please suggest, how to disable dynamic port mapping, and use static port range mapping (20000-25000) only? I assume, this will increase speedup of my system. Thanks, Oleg 2011-04-22 18:14:45.590723 [DEBUG] switch_channel.c:2813 (sofia/internal/sip:1001@192.168.1.151:5060) Callstate Change RINGING -> ACTIVE . . . . 2011-04-22 18:14:45.750984 [DEBUG] switch_core_session.c:1116 Send signal sofia/internal/sip:1000@192.168.1.152:5060 [BREAK] 2011-04-22 18:14:45.750984 [DEBUG] switch_core_session.c:1288 Session 57 (sofia/internal/sip:1000@192.168.1.152:5060) Locked, Waiting on external entities <5s delay> 2011-04-22 18:14:50.018621 [DEBUG] sofia_reg.c:1765 Changing expire time to 109 by request of proxy sip:callcentric.com 2011-04-22 18:14:50.209565 [DEBUG] switch_nat.c:502 mapped public port 20794 protocol UDP to localport 20794 2011-04-22 18:14:50.341416 [DEBUG] sofia_reg.c:1765 Changing expire time to 104 by request of proxy sip:callcentric.com <5s delay> 2011-04-22 18:14:55.213775 [DEBUG] switch_nat.c:502 mapped public port 20795 protocol UDP to localport 20795 2011-04-22 18:14:55.213775 [DEBUG] sofia_glue.c:3001 AUDIO RTP [sofia/external/2404760839@66.54.140.46] 192.168.1.5 port 20794 -> 204.11.192.22 port 60140 codec: 0 ms: 20 2011-04-22 18:14:55.213775 [DEBUG] switch_rtp.c:1623 Starting timer [soft] 160 bytes per 20ms