IAX2 calls go silent in 1.4 1.4 seems to send invalid miniframe packets: Here's an ethereal trace: 1 0.000000 192.168.8.38 -> 212.44.92.99 IAX2 IAX, source call# 84, timestamp 16ms NEW 2 0.000313 212.44.92.99 -> 192.168.8.38 IAX2 IAX, source call# 2, timestamp 3ms AUTHREQ 3 0.000719 192.168.8.38 -> 212.44.92.99 IAX2 IAX, source call# 84, timestamp 19ms AUTHREP 4 0.003076 212.44.92.99 -> 192.168.8.38 IAX2 IAX, source call# 2, timestamp 6ms ACCEPT 5 0.003631 192.168.8.38 -> 212.44.92.99 IAX2 IAX, source call# 84, timestamp 6ms ACK 6 0.003671 212.44.92.99 -> 192.168.8.38 IAX2 Control, source call# 2, timestamp 9ms ANSWER 7 0.003954 192.168.8.38 -> 212.44.92.99 IAX2 IAX, source call# 84, timestamp 9ms ACK 8 0.018850 192.168.8.38 -> 212.44.92.99 IAX2 Voice, source call# 84, timestamp 40ms, Raw mu-law data (G.711) 9 0.018979 212.44.92.99 -> 192.168.8.38 IAX2 IAX, source call# 2, timestamp 40ms ACK 10 0.038825 192.168.8.38 -> 212.44.92.99 IAX2 Mini packet, source call# 84, timestamp 60ms, Raw mu-law data (G.711) (more mini packets from 192.168.8.38 -> 212.44.92.99) 59 1.006042 212.44.92.99 -> 192.168.8.38 IAX2 Voice, source call# 2, timestamp 1020ms, Raw mu-law data (G.711) 60 1.006638 192.168.8.38 -> 212.44.92.99 IAX2 IAX, source call# 84, timestamp 1020ms ACK 61 1.018886 192.168.8.38 -> 212.44.92.99 IAX2 Mini packet, source call# 84, timestamp 1040ms, Raw mu-law data (G.711) We then get the garbled frame: 62 1.037614 212.44.92.99 -> 192.168.8.38 IAX2 0000 00 0e a6 96 22 bb 00 14 85 c7 1e 45 08 00 45 00 ...."......E..E. 0010 00 c8 4e b9 00 00 40 11 32 0e d4 2c 5c 63 c0 a8 ..N...@.2..,\c.. 0020 08 26 11 d9 11 d9 00 b4 fa 23 00 00 01 00 00 00 .&.......#...... 0030 00 00 00 02 00 a0 78 78 78 79 79 79 79 79 79 78 ......xxxyyyyyyx 0040 79 79 78 79 79 79 7a 7a 7b 7b 7b 7b 7b 7c 7d 7e yyxyyyzz{{{{{|}~ 0050 7e 7d 7d 7e ff ff ff 7e 7e 7e ff ff ff ff ff ff ~}}~...~~~...... 0060 ff fe fe ff fe fe fe fd fd fd fe fe fe ff ff ff ................ 0070 7d 7e 7e 7e 7e 7e 7d 7d 7d 7c 7c 7c 7b 7b 7b 7c }~~~~~}}}|||{{{| 0080 7b 7b 7d 7d 7d 7d 7e ff ff ff fe fe fe fc fd fd {{}}}}~......... 0090 fd fd fd fc fd fd fe fe fe fd fd fe ff ff fe fe ................ 00a0 fe fe fd fd fd fe fe fe ff ff ff 7d 7e 7e 7d 7e ...........}~~}~ 00b0 7e 7d 7d 7d 7d 7c 7c 7c 7d 7c 7c 7b 7c 7c 7d 7d ~}}}}|||}||{||}} 00c0 7d 7e 7e 7e 7d 7d 7e ff ff ff fe fe fe ff ff fe }~~~}}~......... 00d0 7e 7e ff 7d 7d 7e ~~.}}~ It looks like a meta (trunk) frame, but it doesn't have Meta Command or Cmd data set to valid values. The length is plausible for a Meta frame carrying a single (G.711) packet.