[SR-Users] SDP getting modified.

Hi everyone, Here is my setup SIP Client (MacBook) <=> Kamailio (AWS) <=> Freeswitch (AWS) When I initiate a call from Client, audio won't be sent out, but the client can receive audio. (When the client receives the call everything works fine). I started to trace the SIP message using tdpdump. And here is an interesting thing. Kamailio sends the following SDP message while sending 200 OK v=0 o=FreeSWITCH 1714278184 1714278185 IN IP4 *<freeswitch-ip-address>* s=FreeSWITCH c=IN IP4 *<freeswitch-ip-address>* t=0 0 m=audio 27644 RTP/AVP 120 101 a=rtpmap:120 opus/48000/2 a=fmtp:120 useinbandfec=1 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-15 a=ptime:20 But on my computer where SIP client is running I receive following message v=0 o=FreeSWITCH 1714278184 1714278185 IN IP4 *<kamailio-ip-address>* s=FreeSWITCH c=IN IP4 *<kamailio-ip-address>* t=0 0 m=audio 27644 RTP/AVP 120 101 a=rtpmap:120 opus/48000/2 a=fmtp:120 useinbandfec=1 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-15 a=ptime:20 Somehow, somewhere, somebody is modifying the IP address in the SDP message, hence the SIP client is sending audio to "Kamailio" instead of "Freeswitch" server. My initial guess was my router might be modifying it. After checking the router settings I found SIP ALG is enabled. I disabled it, yet no use. I changed my internet connection to a different provider and things started working. SDP is not getting modified. Have you ever faced such an issue where someone/something is modifying the SDP messages. How did you debug to figure out which component was modifying it? And common fixes for such weird situations? Thanks and Regards, Pavan Kumar