Provided by: irtt_0.9.0-2_amd64 bug


       irtt-server - Isochronous Round-Trip Time Server


       irtt server [args]


       irtt server is the server for irtt(1) (irtt.html).


       -b addresses
              Bind addresses (default “:2112”), comma separated list of:

              Format        Address Type
              :port         unspecified  address  with port,
                            use with care
              host          host with default port 2112, see
                            Host formats below
              host:port     host  with  specified  port, see
                            Host formats below
              %iface        all addresses on interface iface
                            with default port 2112
              %iface:port   all addresses on interface iface
                            with port

              Note: iface strings may contain * to match multiple interfaces

       -d duration
              Max test duration, or 0 for no maximum (default 0s, see Duration units below)

       -i interval
              Min send interval, or 0 for no minimum (default 10ms, see Duration units below)

       -l length
              Max packet length (default 0), or 0 for no maximum.   Numbers  less  than  size  of
              required headers will cause test packets to be dropped.

              Add HMAC with key (0x for hex) to all packets, provides:

              · Dropping of all packets without a correct HMAC

              · Protection for server against unauthorized discovery and use

              Timeout  for  closing  connections if no requests received on a connection (default
              1m0s, see Duration units below).  0 means no timeout (not  recommended,  especially
              on public servers).  Max client interval will be restricted to timeout/4.

              Packet burst allowed before enforcing minimum interval (default 5)

              Payload fill if not requested (default pattern:69727474).  Possible values include:

              Value        Fill
              none         Echo client payload (insecure on
                           public servers)

              rand         Use  random  bytes   from   Go's
              pattern:XX   Use  repeating  pattern  of  hex
                           (default 69727474)

              Comma separated patterns of fill requests to allow (default rand).  See options for
              –fill.  Notes:

              · Patterns may contain * for matching

              · Allowing non-random fills insecure on public servers

              · Use --allow-fills=“” to disallow all fill requests

              Timestamp modes to allow (default dual).  Possible values:

              Value    Allowed Timestamps
              none     Don't allow any timestamps
              single   Allow  a single timestamp (send,
                       receive or midpoint)
              dual     Allow dual timestamps

              Don't allow setting dscp (default false)

              Set source IP address on all outgoing packets  from  listeners  on  unspecified  IP
              addresses  (use  for  more  reliable  reply  routing, but increases per-packet heap

              Sets garbage collection mode (default on).  Possible values:

              Value   Meaning
              on      Garbage collector always on
              off     Garbage collector always off
              idle    Garbage collector  enabled  only
                      when idle

              Lock request handling goroutines to OS threads

       -h     Show help

       -v     Show version

   Host formats
       Hosts  may be either hostnames (for IPv4 or IPv6) or IP addresses.  IPv6 addresses must be
       surrounded by brackets and may include a zone after the % character.  Examples:

       Type              Example
       IPv4 IP 
       IPv6 IP           [2001:db8:8f::2/32]
       IPv4/6 hostname   localhost

       Note: IPv6 addresses must be quoted in most shells.

   Duration units
       Durations are a sequence of decimal numbers, each with optional fraction, and unit suffix,
       such as: “300ms”, “1m30s” or “2.5m”.  Sanity not enforced.

       Suffix   Unit
       h        hours
       m        minutes
       s        seconds
       ms       milliseconds
       ns       nanoseconds


       Running  an  IRTT  server  that's  open  to  the  outside  world  requires some additional
       attention.  For starters, irtt server's command  line  flags  should  be  used  to,  at  a

       · Restrict  the  duration  (-d),  interval (-i) and length (-l) of tests, particularly for
         public servers

       · Set an HMAC key (--hmac) for private servers to prevent unauthorized discovery and use

       In addition, there are various systemd(1) options available for  securing  services.   The
       irtt.service  file  included  with  the  distribution sets many commonly used options, but
       should not be considered exhaustive.

       To secure a server for public use, additional steps may be taken that are outside  of  the
       scope of this documentation, including but not limited to:

       · Setting up an iptables firewall (only UDP port 2112 must be open)

       · Setting up a chroot jail

       It  should be noted that there are no known security vulnerabilities in the Go language at
       this time, and the steps above, in particular the chroot jail, may or  may  not  serve  to
       enhance  security  in any way.  Go-based servers are generally regarded as safe because of
       Go's high-level language constructs for memory management, and at this time IRTT makes  no
       use of Go's unsafe ( package.


       irtt server exits with one of the following status codes:

       Code   Meaning
       0      Success
       1      Runtime error
       2      Command line error
       3      Two interrupt signals received


       $ irtt server
              Starts the server and listens on all addresses (unspecified address)

       $ irtt server -d 30s -i 20ms -l 256 --fill=rand --allow-fills=“”
              Starts  the  server and listens on all addresses, setting the maximum test duration
              to 30 seconds, minimum interval to 20 ms, and maximum packet length to  256  bytes.
              Disallows  fill  requests  and  forces  all return packets to be filled with random

       $ irtt server -b --hmac=secret
              Starts the server and binds to IPv4 address, port 64381.  Requires a
              valid HMAC on all packets with the key secret, otherwise packets are dropped.


       irtt(1) (irtt.html), irtt-client(1) (irtt-client.html)

       IRTT GitHub repository (