Hi, i'm an user from freeswitch because my trunk's provider is using a freeswitch. i can't give you the configuration using by my provider and i can't give you any trace from freeswitch but i'd like explain my problem to know if anyone have an idea from what can cause my issue. My situation: Freeswitch (public ip A.A.A.A) <----> WAN <---> (my public ip B.B.B.B) FIREWALL <----> (my private ip C.C.C.C) IPBX ALCATEL During a call, after invite or reinvite, Freeswitch send me RTP DATA on wrong RTP port... For sample: I receive a call, after invite from FS and OK from my IPBX, we have a communication who is good. We hear on the two sides. FS<-> A.A.A.A:RTPA1 -------- B.B.B.B:RTPB1 ---------------- C.C.C.C:RTPC1 <> IPBX If i need to hold the call, all is ok. My holding music is hearing. FS<-> A.A.A.A:RTPA1 -------- B.B.B.B:RTPB1 ---------------- C.C.C.C:RTPC1 <> IPBX FS<-- A.A.A.A:SIPA1 -------- B.B.B.B:SIPB1 -------------- C.C.C.C:SIPC1 <-- IPBX (INVITE) (OK) FS --> A.A.A.A:SIPA1 ------- B.B.B.B:SIPB1 -------------- C.C.C.C:SIPC1 --> IPBX FS<-> A.A.A.A:RTPA1 -------- B.B.B.B:RTPB2 ---------------- C.C.C.C:RTPC2 <> IPBX But when i unhold the call, "randomly", FS send me RTP DATA on the RTP port used before the unhold.. And we have no sound on the two sides... Case good: FS<-> A.A.A.A:RTPA1 -------- B.B.B.B:RTPB2 ---------------- C.C.C.C:RTPC2 <> IPBX FS<-- A.A.A.A:SIPA1 -------- B.B.B.B:SIPB1 -------------- C.C.C.C:SIPC1 <-- IPBX (INVITE) (OK) FS --> A.A.A.A:SIPA1 ------- B.B.B.B:SIPB1 -------------- C.C.C.C:SIPC1 --> IPBX FS<-> A.A.A.A:RTPA1 -------- B.B.B.B:RTPB3 ---------------- C.C.C.C:RTPC3 <> IPBX Case bad: FS<-> A.A.A.A:RTPA1 -------- B.B.B.B:RTPB2 ---------------- C.C.C.C:RTPC2 <> IPBX FS<-- A.A.A.A:SIPA1 -------- B.B.B.B:SIPB1 -------------- C.C.C.C:SIPC1 <-- IPBX (INVITE) (OK) FS --> A.A.A.A:SIPA1 ------- B.B.B.B:SIPB1 -------------- C.C.C.C:SIPC1 --> IPBX FS<-- A.A.A.A:RTPA1 -------- B.B.B.B:RTPB3 ---------------- C.C.C.C:RTPC3 <-- IPBX FS--> A.A.A.A:RTPA1 -------- B.B.B.B:RTPB2 ---------------- C.C.C.C:RTPC2 --> IPBX I don't understand why the rtp port is not good updating by freeswitch randomly. I know freeswitch don't use the port that my IPBX give in INVITE packet because it's not the good with the nat from my firewall. I suppose that's the "NDLB-connectile-dysfunction" who is used by freeswitch to find the good rtp port. If with a little congestion, Freeswitch receive after my reinvite, one or two RTP packet from previous RTP DATA, Freeswitch can use the wrong RTP port? Is there a parameter to ignore after reinvite the five first RTP packet to autoadjust the RTP port? Thanks to all helping and sorry for my poor english. Best regards