# phpman > man > mtr-packet(8)

[MTR-PACKET(8)](https://www.chedong.com/phpMan.php/man/MTR-PACKET/8/markdown)                           System Administration                          [MTR-PACKET(8)](https://www.chedong.com/phpMan.php/man/MTR-PACKET/8/markdown)





## 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 ⟨<https://pypi.org/project/mtrpacket/>⟩

## CONTACT INFORMATION
       For the latest version, see the mtr web page at ⟨<http://www.bitwizard.nl/mtr/>⟩

       For patches, bug reports, or feature requests, please open an issue on GitHub  at:  ⟨https://
       github.com/traviscross/mtr⟩.

## SEE ALSO
       [**mtr**(8)](https://www.chedong.com/phpMan.php/man/mtr/8/markdown), [**icmp**(7)](https://www.chedong.com/phpMan.php/man/icmp/7/markdown), [**tcp**(7)](https://www.chedong.com/phpMan.php/man/tcp/7/markdown), [**udp**(7)](https://www.chedong.com/phpMan.php/man/udp/7/markdown), TCP/IP Illustrated (Stevens, ISBN 0201633469).



mtr-packet                                      0.95                                   [MTR-PACKET(8)](https://www.chedong.com/phpMan.php/man/MTR-PACKET/8/markdown)