Yesterday I had a verto call in which the <video> contained a remote echo (which is how we configure it) but there was no audio out nor in (confirmed by getStats showing zero audio bytes out or in). I was using: FreeSWITCH Version 1.10.4-release+git~20200805T110119Z~133fc2c870~64bit (git 133fc2c 2020-08-05 11:01:19Z 64bit) from Chrome84/Win10 I noticed the video candidates included a relay but the audio ones didn't: f6e23797-4ad2-b761-2a6d-97846c122d7e m=audio 62058 UDP/TLS/RTP/SAVPF 111 103 104 9 0 8 106 105 13 110 112 113 126 f6e23797-4ad2-b761-2a6d-97846c122d7e c=IN IP4 192.168.208.1 f6e23797-4ad2-b761-2a6d-97846c122d7e a=rtcp:9 IN IP4 0.0.0.0 f6e23797-4ad2-b761-2a6d-97846c122d7e a=candidate:1252570982 1 udp 2122260223 192.168.208.1 62058 typ host generation 0 network-id 1 f6e23797-4ad2-b761-2a6d-97846c122d7e a=candidate:854729925 1 udp 2122194687 172.20.4.169 62059 typ host generation 0 network-id 2 network-cost 10 f6e23797-4ad2-b761-2a6d-97846c122d7e a=candidate:69946262 1 tcp 1518280447 192.168.208.1 9 typ host tcptype active generation 0 network-id 1 f6e23797-4ad2-b761-2a6d-97846c122d7e a=candidate:2087835701 1 tcp 1518214911 172.20.4.169 9 typ host tcptype active generation 0 network-id 2 network-cost 10 f6e23797-4ad2-b761-2a6d-97846c122d7e m=video 13143 UDP/TLS/RTP/SAVPF 96 97 98 99 100 101 102 122 127 121 125 107 108 109 124 120 123 119 114 115 116 f6e23797-4ad2-b761-2a6d-97846c122d7e c=IN IP4 35.160.47.89 f6e23797-4ad2-b761-2a6d-97846c122d7e a=rtcp:9 IN IP4 0.0.0.0 f6e23797-4ad2-b761-2a6d-97846c122d7e a=candidate:1252570982 1 udp 2122260223 192.168.208.1 62060 typ host generation 0 network-id 1 f6e23797-4ad2-b761-2a6d-97846c122d7e a=candidate:854729925 1 udp 2122194687 172.20.4.169 62061 typ host generation 0 network-id 2 network-cost 10 f6e23797-4ad2-b761-2a6d-97846c122d7e a=candidate:69946262 1 tcp 1518280447 192.168.208.1 9 typ host tcptype active generation 0 network-id 1 f6e23797-4ad2-b761-2a6d-97846c122d7e a=candidate:2087835701 1 tcp 1518214911 172.20.4.169 9 typ host tcptype active generation 0 network-id 2 network-cost 10 f6e23797-4ad2-b761-2a6d-97846c122d7e a=candidate:3112167340 1 udp 25042943 35.jj.kk.mm 13143 typ relay raddr 210.55.134.98 rport 53504 generation 0 network-id 2 network-cost 10 The relay was chosen for video, and it appeared that the same candidate was going to be chosen for audio, but then an "AUDIO RTP" suggests it chose a private IPv4. And it seems that private IPv4 wasn't treated as a peer-reflexive candidate, so the media couldn't be routed... f6e23797-4ad2-b761-2a6d-97846c122d7e 2020-08-19 05:14:33.753568 [DEBUG] switch_core_media.c:4338 Choose rtp candidate, index 2, 35.jj.kk.mm:13143 f6e23797-4ad2-b761-2a6d-97846c122d7e 2020-08-19 05:14:33.753568 [DEBUG] switch_core_media.c:4104 verto.rtc/1200_a6dd33a4-1def-447c-a62a-ae807bb92da6_v-1*s-4 choosing family v4 f6e23797-4ad2-b761-2a6d-97846c122d7e 2020-08-19 05:14:33.753568 [DEBUG] switch_core_media.c:4349 Choose same candidate, index 0, for rtcp based on rtcp-mux attribute 35.jj.kk.mm:13143 f6e23797-4ad2-b761-2a6d-97846c122d7e 2020-08-19 05:14:33.753568 [DEBUG] switch_core_media.c:4401 setting remote video ice addr to index 2 35.jj.kk.mm:13143 based on candidate f6e23797-4ad2-b761-2a6d-97846c122d7e 2020-08-19 05:14:33.753568 [DEBUG] switch_core_media.c:4436 Setting remote rtcp video addr to 35.jj.kk.mm:13143 based on candidate f6e23797-4ad2-b761-2a6d-97846c122d7e 2020-08-19 05:14:33.753568 [DEBUG] switch_core_media.c:8663 AUDIO RTP [verto.rtc/1200_a6dd33a4-1def-447c-a62a-ae807bb92da6_v-1*s-4] 10.0.0.100 port 26610 -> 192.168.208.1 port 62058 codec: 111 ms: 20 Am I interpreting the log correctly? Is there a way to avoid this? Note that in /usr/local/freeswitch/conf/autoload_configs/acl.conf.xml we already deny private IPv4 (although I think we should allow them so they could be used peer-reflexively): <list name="disallow-privateIPv4" default="allow"> <node type="deny" host="10.0.0.0" mask="255.0.0.0"/> <node type="deny" host="172.16.0.0" mask="255.240.0.0"/> <node type="deny" host="192.168.0.0" mask="255.255.0.0"/> </list> Cheers, David