man > mtr-packet(8)

MTR-PACKET(8)                           System Administration                          MTR-PACKET(8)





NAME
       mtr-packet - send and receive network probes

DESCRIPTION
       mtr-packet  is  a tool for sending network probes to measure network connectivity and perfor‐
       mance.  Many network probes can be sent simultaneously by a single process instance  of  mtr-
       packet  and additional probes can be generated by an instance of mtr-packet which already has
       network probes in flight.  It is intended to be used by programs which invoke  it  with  Unix
       pipes attached to its standard input and output streams.

       mtr-packet  reads command requests from stdin, each separated by a newline character, and re‐
       sponds with command replies to stdout, also each separated by a newline character.  The  syn‐
       tactic structure of requests and replies are the same.  The following format is used:

              TOKEN COMMAND [ARGUMENT-NAME ARGUMENT-VALUE ...]

       TOKEN  is a unique integer value.  The same value will be used as the TOKEN for the response.
       This is necessary for associating replies with requests, as commands may be  completed  in  a
       different order than they are requested.  The invoker of mtr-packet should always use the TO‐
       KEN value to determine which command request has completed.

       COMMAND  is  a  string identifying the command request type.  A common command is send-probe,
       which will transmit one network probe.

       ARGUMENT-NAME strings and ARGUMENT-VALUE strings always come in pairs.  It is a syntactic er‐
       ror to provide an ARGUMENT-NAME without a corresponding ARGUMENT-VALUE.  Valid  ARGUMENT-NAME
       strings depend on the COMMAND being used.

REQUESTS
       send-probe
              Send a network probe to a particular IP address.  Either an ip-4 or ip-6 argument must
              be  provided.   A valid send-probe command will reply with reply, no-reply, or ttl-ex‐
              pired.

              The following arguments may be used:

              ip-4 IP-ADDRESS



                     The Internet Protocol version 4 address to probe.



              ip-6 IP-ADDRESS



                     The Internet Protocol version 6 address to probe.



              protocol PROTOCOL



                     The protocol to use for the network probe.  icmp, sctp, tcp,  and  udp  may  be
                     used.  The default protocol is icmp.



              port PORT-NUMBER



                     The destination port to use for sctp, tcp, or udp probes.



              local-ip-4 IP-ADDRESS



                     The local Internet Protocol version 4 address to use when sending probes.



              local-ip-6 IP-ADDRESS



                     The local Internet Protocol version 6 address to use when sending probes.



              local-port PORT-NUMBER



                     For udp probes, the local port number from which to send probes.



              timeout TIMEOUT-SECONDS



                     The number of seconds to wait for a response to the probe before discarding the
                     probe as lost, and generating a no-reply command reply.



              ttl TIME-TO-LIVE



                     The  time-to-live  value  for  the Internet Protocol packet header used in con‐
                     structing the probe.  This value determines the number of network hops  through
                     which  the  probe will travel before a response is generated by an intermediate
                     network host.



              size PACKET-SIZE



                     The size of the packet used to send the probe, in bytes, including the Internet
                     Protocol header and transport protocol header.



              bit-pattern PATTERN-VALUE



                     The packet payload is filled with bytes of the value specified.  Valid  pattern
                     values are in the range 0 through 255.



              tos TYPE-OF-SERVICE



                     In  the  case  of  IPv4, the "type of service" field in the IP header is set to
                     this value.  In the case of IPv6, the "traffic class" field is set.



              mark ROUTING-MARK



                     The packet mark value to be used by mark-based  routing.   (Available  only  on
                     Linux.)



       check-support
              Check  for  support for a particular feature in this version of mtr-packet and in this
              particular operating environment.  check-support will reply with feature-supported.  A
              feature argument is required.



              feature FEATURE-NAME



                     The name of a feature requested.



              Some features which can be checked are send-probe, ip-4, ip-6, icmp, sctp,  tcp,  udp,
              and mark.  The feature version can be checked to retrieve the version of mtr-packet.

REPLIES
       reply  The  destination  host  received the send-probe probe and replied.  Arguments of reply
              are:



              ip-4 IP-ADDRESS



                     The Internet Protocol version 4 address of the host which replied to the probe.




              ip-6 IP-ADDRESS



                     The Internet Protocol version 6 address of the host which replied to the probe.




              round-trip-time TIME



                     The time which passed between the transmission of the probe and  its  response.
                     The time is provided as a integral number of microseconds elapsed.



       no-reply
              No response to the probe request was received before the timeout expired.

       ttl-expired
              The  time-to-live  value  of the transmitted probe expired before the probe arrived at
              its intended destination.  Arguments of ttl-expired are:



              ip-4 IP-ADDRESS



                     The Internet Protocol version 4 address of the host at which  the  time-to-live
                     value expired.



              ip-6 IP-ADDRESS



                     The  Internet  Protocol version 6 address of the host at which the time-to-live
                     value expired.



              round-trip-time TIME



                     The time which passed between the transmission of the probe and  its  response.
                     The time is provided as a integral number of microseconds elapsed.



              mpls MPLS-LABEL-LIST



                     A  list  of  Multiprotocol  Label  Switching values returned with the probe re‐
                     sponse.  If the mpls argument is present, one or more MPLS labels will be  rep‐
                     resented  by  a  comma  separated  list  of values.  The values are provided in
                     groups of four.  The first four values in the list correspond to the first MPLS
                     label, the next four values correspond to the second MPLS  label,  and  so  on.
                     The  values  are provided in this order: label, traffic-class, bottom-of-stack,
                     ttl.



       no-route
              There was no route to the host used in a send-probe request.

       network-down
              A probe could not be sent because the network is down.

       probes-exhausted
              A probe could not be sent because there are already  too  many  unresolved  probes  in
              flight.

       permission-denied
              The operating system denied permission to send the probe with the specified options.

       invalid-argument
              The command request contained arguments which are invalid.

       feature-support
              A  reply to provided to check-support indicating the availability of a particular fea‐
              ture.  The argument provided is:



              support PRESENT



                     In most cases, the PRESENT value will be either ok, indicating the  feature  is
                     supported, or no, indicating no support for the feature.

                     In  the  case  that  version is the requested FEATURE-NAME, the version of mtr-
                     packet is provided as the PRESENT value.



EXAMPLES
       A controlling program may start mtr-packet as a child process and issue the following command
       on stdin:

              42 send-probe ip-4 127.0.0.1

       This will send a network probe to the loopback interface.  When  the  probe  completes,  mtr-
       packet will provide a response on stdout such as the following:

              42 reply ip-4 127.0.0.1 round-trip-time 126

       This indicates that the loopback address replied to the probe, and the round-trip time of the
       probe was 126 microseconds.

       In  order to trace the route to a remote host, multiple send-probe commands, each with a dif‐
       ferent ttl value, are used.

              11 send-probe ip-4 8.8.8.8 ttl 1
              12 send-probe ip-4 8.8.8.8 ttl 2
              13 send-probe ip-4 8.8.8.8 ttl 3
              ...

       Each intermediate host would respond with a ttl-expired message,  and  the  destination  host
       would respond with a reply:

              11 ttl-expired ip-4 192.168.254.254 round-trip-time 1634
              12 ttl-expired ip-4 184.19.243.240 round-trip-time 7609
              13 ttl-expired ip-4 172.76.20.169 round-trip-time 8643
              14 ttl-expired ip-4 74.40.1.101 round-trip-time 9755
              15 ttl-expired ip-4 74.40.5.126 round-trip-time 10695
              17 ttl-expired ip-4 108.170.245.97 round-trip-time 14077
              16 ttl-expired ip-4 74.40.26.131 round-trip-time 15253
              18 ttl-expired ip-4 209.85.245.101 round-trip-time 17080
              19 reply ip-4 8.8.8.8 round-trip-time 17039

       Note  that  the replies in this example are printed out of order.  (The reply to probe 17 ar‐
       rives prior to the reply to probe 16.)  This is the reason that it is important to send  com‐
       mands  with  unique  token  values, and to use those token values to match replies with their
       originating commands.

LANGUAGE BINDINGS
       A Python 3.x package for sending asynchronous network probes using mtr-packet  is  available.
       See ]8;;https://pypi.org/project/mtrpacket/\https://pypi.org/project/mtrpacket/]8;;\

CONTACT INFORMATION
       For the latest version, see the mtr web page at ]8;;http://www.bitwizard.nl/mtr/\http://www.bitwizard.nl/mtr/]8;;\

       For  patches,  bug  reports, or feature requests, please open an issue on GitHub at: ]8;;https://github.com/traviscross/mtr\https://
       github.com/traviscross/mtr]8;;\.

SEE ALSO
       mtr(8), icmp(7), tcp(7), udp(7), TCP/IP Illustrated (Stevens, ISBN 0201633469).

mtr-packet                                      0.95                                   MTR-PACKET(8)