What steps will reproduce the problem? 1. start coturn with default configuration 2. call turnutils_uclient -T -n 50 -l 10000 host 3.

What is the expected output? What do you see instead? I see Total lost packets 100 (100.000000%)

What version of the product are you using? On what operating system? Linux32, Version Coturn-4.2.1.2

Please provide any additional information below.

plus, I dont get any error or warning in log.

Comment deleted

taking it back for investigation

I tested it on several systems (BSDs and Linuxes) with the latest version and I could not reproduce the problem. This is the output that I have on a Linux Mint:

oleg@limper ~/c/coturn $ ./examples/scripts/longtermsecure/secure_tcp_client_c2c_tcp_relay.sh -m 50 -l 10000 0: Total connect time is 5 0: 2450 connections are completed 0: start_mclient: msz=50, tot_send_msgs=0, tot_recv_msgs=0, tot_send_bytes ~ 0, tot_recv_bytes ~ 0 1: start_mclient: msz=50, tot_send_msgs=0, tot_recv_msgs=0, tot_send_bytes ~ 0, tot_recv_bytes ~ 0 2: start_mclient: msz=50, tot_send_msgs=13, tot_recv_msgs=13, tot_send_bytes ~ 130000, tot_recv_bytes ~ 130000 3: start_mclient: msz=50, tot_send_msgs=317, tot_recv_msgs=317, tot_send_bytes ~ 3170000, tot_recv_bytes ~ 3170000 4: start_mclient: msz=50, tot_send_msgs=990, tot_recv_msgs=986, tot_send_bytes ~ 9900000, tot_recv_bytes ~ 9860000 5: start_mclient: msz=50, tot_send_msgs=2263, tot_recv_msgs=2251, tot_send_bytes ~ 22630000, tot_recv_bytes ~ 22510000 6: start_mclient: msz=50, tot_send_msgs=4140, tot_recv_msgs=4100, tot_send_bytes ~ 41400000, tot_recv_bytes ~ 41000000 7: start_mclient: msz=50, tot_send_msgs=6518, tot_recv_msgs=6453, tot_send_bytes ~ 65180000, tot_recv_bytes ~ 64530000 8: start_mclient: msz=50, tot_send_msgs=9034, tot_recv_msgs=8921, tot_send_bytes ~ 90340000, tot_recv_bytes ~ 89210000 9: start_mclient: msz=50, tot_send_msgs=11552, tot_recv_msgs=11411, tot_send_bytes ~ 115520000, tot_recv_bytes ~ 114110000 10: start_mclient: msz=50, tot_send_msgs=14063, tot_recv_msgs=13886, tot_send_bytes ~ 140630000, tot_recv_bytes ~ 138860000 11: start_mclient: msz=50, tot_send_msgs=16575, tot_recv_msgs=16346, tot_send_bytes ~ 165750000, tot_recv_bytes ~ 163460000 11: start_mclient: msz=50, tot_send_msgs=18838, tot_recv_msgs=18576, tot_send_bytes ~ 188380000, tot_recv_bytes ~ 185760000 13: start_mclient: msz=50, tot_send_msgs=21357, tot_recv_msgs=21057, tot_send_bytes ~ 213570000, tot_recv_bytes ~ 210570000 14: start_mclient: msz=50, tot_send_msgs=23869, tot_recv_msgs=23537, tot_send_bytes ~ 238690000, tot_recv_bytes ~ 235370000 15: start_mclient: msz=50, tot_send_msgs=26388, tot_recv_msgs=26014, tot_send_bytes ~ 263880000, tot_recv_bytes ~ 260140000 16: start_mclient: msz=50, tot_send_msgs=28907, tot_recv_msgs=28499, tot_send_bytes ~ 289070000, tot_recv_bytes ~ 284990000 17: start_mclient: msz=50, tot_send_msgs=31415, tot_recv_msgs=30958, tot_send_bytes ~ 314150000, tot_recv_bytes ~ 309580000 18: start_mclient: msz=50, tot_send_msgs=33942, tot_recv_msgs=33437, tot_send_bytes ~ 339420000, tot_recv_bytes ~ 334370000 19: start_mclient: msz=50, tot_send_msgs=36453, tot_recv_msgs=35897, tot_send_bytes ~ 364530000, tot_recv_bytes ~ 358970000 20: start_mclient: msz=50, tot_send_msgs=38968, tot_recv_msgs=38379, tot_send_bytes ~ 389680000, tot_recv_bytes ~ 383790000 21: start_mclient: msz=50, tot_send_msgs=41484, tot_recv_msgs=40853, tot_send_bytes ~ 414840000, tot_recv_bytes ~ 408530000 22: start_mclient: msz=50, tot_send_msgs=43985, tot_recv_msgs=43316, tot_send_bytes ~ 439850000, tot_recv_bytes ~ 433160000 23: start_mclient: msz=50, tot_send_msgs=46189, tot_recv_msgs=45498, tot_send_bytes ~ 461890000, tot_recv_bytes ~ 454980000 24: start_mclient: msz=50, tot_send_msgs=48015, tot_recv_msgs=47311, tot_send_bytes ~ 480150000, tot_recv_bytes ~ 473110000 25: start_mclient: msz=50, tot_send_msgs=49242, tot_recv_msgs=48535, tot_send_bytes ~ 492420000, tot_recv_bytes ~ 485350000 26: start_mclient: msz=50, tot_send_msgs=49876, tot_recv_msgs=49162, tot_send_bytes ~ 498760000, tot_recv_bytes ~ 491620000 27: start_mclient: msz=50, tot_send_msgs=50000, tot_recv_msgs=49285, tot_send_bytes ~ 500000000, tot_recv_bytes ~ 492850000 28: start_mclient: msz=50, tot_send_msgs=50000, tot_recv_msgs=49285, tot_send_bytes ~ 500000000, tot_recv_bytes ~ 492850000 28: start_mclient: msz=50, tot_send_msgs=50000, tot_recv_msgs=49285, tot_send_bytes ~ 500000000, tot_recv_bytes ~ 492850000 29: start_mclient: msz=50, tot_send_msgs=50000, tot_recv_msgs=49285, tot_send_bytes ~ 500000000, tot_recv_bytes ~ 492850000 31: start_mclient: msz=50, tot_send_msgs=50000, tot_recv_msgs=49285, tot_send_bytes ~ 500000000, tot_recv_bytes ~ 492850000 32: start_mclient: msz=48, tot_send_msgs=50000, tot_recv_msgs=49285, tot_send_bytes ~ 500000000, tot_recv_bytes ~ 492850000 33: start_mclient: msz=41, tot_send_msgs=50000, tot_recv_msgs=49285, tot_send_bytes ~ 500000000, tot_recv_bytes ~ 492850000 34: start_mclient: msz=31, tot_send_msgs=50000, tot_recv_msgs=49285, tot_send_bytes ~ 500000000, tot_recv_bytes ~ 492850000 35: start_mclient: msz=20, tot_send_msgs=50000, tot_recv_msgs=49285, tot_send_bytes ~ 500000000, tot_recv_bytes ~ 492850000 36: start_mclient: msz=7, tot_send_msgs=50000, tot_recv_msgs=49285, tot_send_bytes ~ 500000000, tot_recv_bytes ~ 492850000 36: start_mclient: tot_send_msgs=50000, tot_recv_msgs=49285 36: start_mclient: tot_send_bytes ~ 500000000, tot_recv_bytes ~ 492850000 36: Total transmit time is 36 36: Total lost packets 715 (1.430000%), total send dropped 0 (0.000000%) 36: Average round trip delay 0.012519 ms; min = 0 ms, max = 20 ms 36: Average jitter 0.132008 ms; min = 0 ms, max = 398 ms

can you please try on remote turn server, not installed on local computer?

We want to separate the network issues from the TURN server / TURN client issues, right ? That's why I was intentiallt running it locally. If it works locally and does not work remotely, then this is a network problem.

OK, but why do we have even that Total lost packets 715 (1.430000%) ?

Because the network load could not be handled in full by the particular kernel and the hardware. Just too high data rate. That's 50 x 10000 x 50 = 25000000 bytes per second that is 200Mbits per second.