I've installed freeswitch on a Raspberry PI 3 with pretty much bog stock config. The only change I've done is to delete the ipv6 profiles and changed the default password. I've connected a few different clients, 3 soft phones and 2 ATAs. When making calls with some of the clients the calls are dropped after 32 seconds. For other clients the calls will proceed for half an hour no issues. I have absolutely no complexity here, it's all internal phones on the local /24 lan. There are no firewalls, traffic only goes via a switch. I have no external SIP gateway, none of the clients are behind a NAT. I've done extensive googling and everything I find talks about NAT issues and VPNs, multiple subnets etc. I'm not running any of that. Packet capture and more details below. Some of the things I've tried - complete OS and freeswitch reinstall on the PI - disable IPv6 on the PI (made a big improvement, now the remote phone rings instantly instead of long delay) - full OS update before installing freeswitch - tried clients with both UDP and TCP - install freeswitch on CentOS 7. - Disable SIP ALG on router (traffic not going through router anyway) - Tried all devices on a different network switch - Tried client options like "use rport" etc What works: - Cisco SPA3102 ATA - Voiper latest version on Windows What doesn't work - Latest Voiper on android - Older version of voiper on windows - Billion 7404VGP - Android version of Voip by antisip TShark capture of a call dropping. IPs are: 192.168.1.245 Freeswitch 192.168.1.225 Windows PC with older copy of voiper 192.168.1.202 Cisco ATA 1 0.000000000 192.168.1.225 â 192.168.1.245 SIP/SDP 1038 Request: INVITE sip:1004@192.168.1.245;transport=UDP | 2 0.005573031 192.168.1.245 â 192.168.1.225 SIP 917 Status: 407 Proxy Authentication Required | 3 0.011167520 192.168.1.225 â 192.168.1.245 SIP 408 Request: ACK sip:1004@192.168.1.245;transport=UDP | 4 0.016217586 192.168.1.225 â 192.168.1.245 SIP/SDP 1314 Request: INVITE sip:1004@192.168.1.245;transport=UDP | 5 0.037157271 192.168.1.245 â 192.168.1.225 SIP 413 Status: 100 Trying | 6 0.094830064 192.168.1.245 â 192.168.1.202 SIP/SDP 1283 Request: INVITE sip:1004@192.168.1.202:5083;transport=tcp | 7 0.115792718 192.168.1.202 â 192.168.1.245 SIP 365 Status: 100 Trying | 8 0.115932040 192.168.1.245 â 192.168.1.202 TCP 54 5060 â 5083 [ACK] Seq=1230 Ack=312 Win=63784 Len=0 9 0.124784941 192.168.1.202 â 192.168.1.245 SIP 526 Status: 180 Ringing | 10 0.124863118 192.168.1.245 â 192.168.1.202 TCP 54 5060 â 5083 [ACK] Seq=1230 Ack=784 Win=63784 Len=0 11 0.151217241 192.168.1.245 â 192.168.1.225 SIP/SDP 1205 Status: 183 Session Progress | 12 2.263254019 192.168.1.202 â 192.168.1.245 SIP/SDP 901 Status: 200 OK | 13 2.263406934 192.168.1.245 â 192.168.1.202 TCP 54 5060 â 5083 [ACK] Seq=1230 Ack=1631 Win=63784 Len=0 14 2.272446033 192.168.1.245 â 192.168.1.202 SIP 471 Request: ACK sip:1004@192.168.1.202:5083;transport=tcp | 15 2.284211777 192.168.1.245 â 192.168.1.225 SIP/SDP 1169 Status: 200 OK | 16 2.469876726 192.168.1.202 â 192.168.1.245 TCP 60 5083 â 5060 [ACK] Seq=1631 Ack=1647 Win=16000 Len=0 17 2.784653094 192.168.1.245 â 192.168.1.225 SIP/SDP 1169 Status: 200 OK | 18 3.785916037 192.168.1.245 â 192.168.1.225 SIP/SDP 1169 Status: 200 OK | 19 5.787085997 192.168.1.245 â 192.168.1.225 SIP/SDP 1169 Status: 200 OK | 20 8.903231371 192.168.1.245 â 192.168.1.225 TCP 54 5060 â 56460 [ACK] Seq=1 Ack=1 Win=501 Len=0 21 8.903781836 192.168.1.225 â 192.168.1.245 TCP 60 [TCP ACKed unseen segment] 56460 â 5060 [ACK] Seq=1 Ack=2 Win=8212 Len=0 22 9.788128841 192.168.1.245 â 192.168.1.225 SIP/SDP 1169 Status: 200 OK | 23 13.788284085 192.168.1.245 â 192.168.1.225 SIP/SDP 1169 Status: 200 OK | 24 17.788442453 192.168.1.245 â 192.168.1.225 SIP/SDP 1169 Status: 200 OK | 25 20.361180947 192.168.1.225 â 192.168.1.245 UDP 60 5060 â 5060 Len=4 26 21.788537538 192.168.1.245 â 192.168.1.225 SIP/SDP 1169 Status: 200 OK | 27 25.788690954 192.168.1.245 â 192.168.1.225 SIP/SDP 1169 Status: 200 OK | 28 29.789847278 192.168.1.245 â 192.168.1.225 SIP/SDP 1169 Status: 200 OK | 29 32.583226442 192.168.1.245 â 192.168.1.202 TCP 54 [TCP Keep-Alive] 5060 â 5083 [ACK] Seq=1646 Ack=1631 Win=63784 Len=0 30 32.584076227 192.168.1.202 â 192.168.1.245 TCP 60 [TCP Keep-Alive ACK] 5083 â 5060 [ACK] Seq=1631 Ack=1647 Win=16000 Len=0 31 33.790019961 192.168.1.245 â 192.168.1.225 SIP/SDP 1169 Status: 200 OK | 32 34.284637050 192.168.1.245 â 192.168.1.225 SIP 704 Request: BYE sip:1002@192.168.1.225:5060;transport=UDP | 33 34.327728390 192.168.1.245 â 192.168.1.202 SIP 672 Request: BYE sip:1004@192.168.1.202:5083;transport=tcp | 34 34.344437951 192.168.1.202 â 192.168.1.245 SIP 381 Status: 200 OK | 35 34.393228415 192.168.1.245 â 192.168.1.202 TCP 54 5060 â 5083 [ACK] Seq=2265 Ack=1958 Win=63784 Len=0 36 34.422931003 192.168.1.225 â 192.168.1.245 SIP 466 Status: 200 OK | 37 38.352414375 192.168.1.225 â 192.168.1.245 TCP 60 [TCP ACKed unseen segment] 56460 â 5060 [PSH, ACK] Seq=1 Ack=2 Win=8212 Len=4 38 38.352610259 192.168.1.245 â 192.168.1.225 TCP 56 [TCP Previous segment not captured] 5060 â 56460 [PSH, ACK] Seq=2 Ack=5 Win=501 Len=2 39 38.393526512 192.168.1.225 â 192.168.1.245 TCP 60 [TCP ACKed unseen segment] 56460 â 5060 [ACK] Seq=5 Ack=4 Win=8212 Len=0 -- This email has been checked for viruses by AVG. https://www.avg.com