turnhammer 0.2.0

A tool to stress-test TURN (RFC 5766) servers
turnhammer-0.2.0 is not a library.


A tool to stress-test TURN (RFC 5766) servers and measure resulting packet loss and RTT.

There are pre-built versions on Github Releases


Usage: turnhammer <server> <username> <password> [-j <parallel-connections>] [-s <pkt-size>] [--pps <pps>] [-d <duration>] [--delay-after-stopping-sender <delay-after-stopping-sender>] [--delay-between-allocations <delay-between-allocations>] [--calc] [-f] [--video] [--audio] [-J] [-C]

  -j, --parallel-connections
                    number of simultaneous connections
  -s, --pkt-size    packet size
  --pps             packets per second
  -d, --duration    experiment duration, seconds
                    seconds to wait and receive after stopping sender
                    microseconds to wait between TURN allocations
  --calc            don't actually run, only calculate bandwidth and traffic
  -f, --force       override bandwidth or traffic limitation
  --video           set pps to 90 and pktsize to 960
  --audio           set pps to 16 and pktsize to 192
  -J, --json        output as JSON instead of plain text
  -C, --no-channels do not use chanels
  --help            display usage information

Output sample:

The test would do approx 11.878 Mbit/s and consume 158.379 megabytes of traffic
My external address:
Allocated 200 TURN clients
Received the first datagram
Received 365652 packets from 384000 window of total 384000 || Loss: 04.7781%   bad loss: 00.0000%
RTT4 brackets: 0-49ms: 00.0000%   180-399ms: 50.7474%  1000-1999ms: 00.0000%
             50-179ms: 44.4745%   500-999ms: 00.0000%      2000+ms: 00.0000%
 <<<  Overall score:  8.2 / 10.0  >>>
Stopping TURN clients

JSON output sample:

$ turnhammer  -J --video -j 3  u153   p1994421   2> /dev/null
,"received_packets":1350 ,"min_max_window":1350 ,"sent_packets":1350
,"loss":0 ,"bad_loss":0
,"rtt4":{"0_49":0 ,"50_179":0 ,"180_399":100 ,"400_999":0 ,"1000_1999":0 ,"2000+":0}


  1. Create a UDP socket bound to
  2. Get external address the socket
  3. Create K other UDP sockets bound to and obtain K allocations from specified TURN server
  4. Add permission to address from "2." to each of that TURN allocations
  5. In each of TURN client instance, send back each data message back to sender. This effectively makes K instances of UDP echo server at TURN side.
  6. From the first UDP socket, send specified number of packets at specified rate to all those "echo servers".
  7. Analyse replies from those "echo servers" and measure packet loss and round-trip times.


Old version

There is old Tokio 0.1-based version of turnhammer, tagged v0.1.0 that can be built with older Rust and may support more old systems. It should work with rustc 1.34.2.