.TH MTR-PACKET 8 "@VERSION@" "mtr-packet" "System Administration" .HP 7 .SH NAME mtr-packet - send and receive network probes .SH DESCRIPTION .B mtr-packet is a tool for sending network probes to measure network connectivity and performance. Many network probes can be sent simultaneously by a single process instance of .B mtr-packet and additional probes can be generated by an instance of .B 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. .LP .B mtr-packet reads command requests from .IR stdin , each separated by a newline character, and responds with command replies to .IR stdout , also each separated by a newline character. The syntactic structure of requests and replies are the same. The following format is used: .LP .RS .I TOKEN .I COMMAND [\c .I ARGUMENT-NAME .I ARGUMENT-VALUE \&...] .RE .LP .I TOKEN is a unique integer value. The same value will be used as the .I 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 .B mtr-packet should always use the .I TOKEN value to determine which command request has completed. .LP .I COMMAND is a string identifying the command request type. A common command is .BR send-probe , which will transmit one network probe. .LP .I ARGUMENT-NAME strings and .I ARGUMENT-VALUE strings always come in pairs. It is a syntactic error to provide an .I ARGUMENT-NAME without a corresponding .IR ARGUMENT-VALUE . Valid .I ARGUMENT-NAME strings depend on the .I COMMAND being used. .SH REQUESTS .TP .B send-probe Send a network probe to a particular IP address. Either an .B ip-4 or .B ip-6 argument must be provided. A valid .B send-probe command will reply with .BR reply , .BR no-reply , or .BR ttl-expired . .IP The following arguments may be used: .IP .B ip-4 .I IP-ADDRESS .HP 14 .IP The Internet Protocol version 4 address to probe. .HP 7 .IP .B ip-6 .I IP-ADDRESS .HP 14 .IP The Internet Protocol version 6 address to probe. .HP 7 .IP .B protocol .I PROTOCOL .HP 14 .IP The protocol to use for the network probe. .BR icmp , .BR sctp , .BR tcp , and .B udp may be used. The default protocol is .BR icmp. .HP 7 .IP .B port .I PORT-NUMBER .HP 14 .IP The destination port to use for .BR sctp , .BR tcp , or .B udp probes. .HP 7 .IP .B local-ip-4 .I IP-ADDRESS .HP 14 .IP The local Internet Procol version 4 address to use when sending probes. .HP 7 .IP .B local-ip-6 .I IP-ADDRESS .HP 14 .IP The local Internet Protocol version 6 address to use when sending probes. .HP 7 .IP .B local-port .I PORT-NUMBER .HP 14 .IP For .B udp probes, the local port number from which to send probes. .HP 7 .IP .B timeout .I TIMEOUT-SECONDS .HP 14 .IP The number of seconds to wait for a response to the probe before discarding the probe as lost, and generating a .B no-reply command reply. .HP 7 .IP .B ttl .I TIME-TO-LIVE .HP 14 .IP The time-to-live value for the Internet Protocol packet header used in constructing 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. .HP 7 .IP .B size .I PACKET-SIZE .HP 14 .IP The size of the packet used to send the probe, in bytes, including the Internet Protocol header and transport protocol header. .HP 7 .IP .B bit-pattern .I PATTERN-VALUE .HP 14 .IP The packet payload is filled with bytes of the value specified. Valid pattern values are in the range 0 through 255. .HP 7 .IP .IP .B tos .I TYPE-OF-SERVICE .HP 14 .IP 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. .HP 7 .IP .B mark .I ROUTING-MARK .HP 14 .IP The packet mark value to be used by mark-based routing. (Available only on Linux.) .HP 7 .TP .B check-support Check for support for a particular feature in this version of .B mtr-packet and in this particular operating environment. .B check-support will reply with .BR feature-supported . A .B feature argument is required. .HP 7 .IP .B feature .I FEATURE-NAME .HP 14 .IP The name of a feature requested. .HP 7 .IP Some features which can be checked are .BR send-probe , .BR ip-4 , .BR ip-6 , .BR icmp , .BR sctp , .BR tcp , .BR udp , and .BR mark . The feature .B version can be checked to retrieve the version of .BR mtr-packet . .SH REPLIES .TP .B reply The destination host received the .B send-probe probe and replied. Arguments of .B reply are: .HP 7 .IP .B ip-4 .I IP-ADDRESS .HP 14 .IP The Internet Protocol version 4 address of the host which replied to the probe. .HP 7 .IP .B ip-6 .I IP-ADDRESS .HP 14 .IP The Internet Protocol version 6 address of the host which replied to the probe. .HP 7 .IP .B round-trip-time .I TIME .HP 14 .IP The time which passed between the transmission of the probe and its response. The time is provided as a integral number of microseconds elapsed. .HP 7 .TP .B no-reply No response to the probe request was received before the timeout expired. .TP .B ttl-expired The time-to-live value of the transmitted probe expired before the probe arrived at its intended destination. Arguments of .B ttl-expired are: .HP 7 .IP .B ip-4 .I IP-ADDRESS .HP 14 .IP The Internet Protocol version 4 address of the host at which the time-to-live value expired. .HP 7 .IP .B ip-6 .I IP-ADDRESS .HP 14 .IP The Internet Protocol version 6 address of the host at which the time-to-live value expired. .HP 7 .IP .B round-trip-time .I TIME .HP 14 .IP The time which passed between the transmission of the probe and its response. The time is provided as a integral number of microseconds elapsed. .HP 7 .IP .B mpls .I MPLS-LABEL-LIST .HP 14 .IP A list of Multiprotocol Label Switching values returned with the probe response. If the .B mpls argument is present, one or more MPLS labels will be represented 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: .IR label , .IR experimental-use , .IR bottom-of-stack , .IR ttl . .HP 7 .TP .B no-route There was no route to the host used in a .B send-probe request. .TP .B network-down A probe could not be sent because the network is down. .TP .B probes-exhausted A probe could not be sent because there are already too many unresolved probes in flight. .TP .B permission-denied The operating system denied permission to send the probe with the specified options. .TP .B invalid-argument The command request contained arguments which are invalid. .TP .B feature-support A reply to provided to .B check-support indicating the availability of a particular feature. The argument provided is: .HP 7 .IP .B support .I PRESENT .HP 14 .IP In most cases, the .I PRESENT value will be either .BR ok , indicating the feature is supported, or .BR no , indicating no support for the feature. .IP In the case that .B version is the requested .IR FEATURE-NAME , the version of .B mtr-packet is provided as the .I PRESENT value. .HP 7 .IP .SH EXAMPLES A controlling program may start .B mtr-packet as a child process and issue the following command on .IR stdin : .LP .RS 42 send-probe ip-4 127.0.0.1 .RE .LP This will send a network probe to the loopback interface. When the probe completes, .B mtr-packet will provide a response on .I stdout such as the following: .LP .RS 42 reply ip-4 127.0.0.1 round-trip-time 126 .RE .LP This indicates that the loopback address replied to the probe, and the round-trip time of the probe was 126 microseconds. .LP In order to trace the route to a remote host, multiple .B send-probe commands, each with a different .B ttl value, are used. .LP .RS 11 send-probe ip-4 220.127.116.11 ttl 1 .RS 0 12 send-probe ip-4 18.104.22.168 ttl 2 .RS 0 13 send-probe ip-4 22.214.171.124 ttl 3 .RS 0 \&... .RE 0 .LP Each interemediate host would respond with a .B ttl-expired message, and the destination host would respond with a .BR reply : .LP .RS 11 ttl-expired ip-4 192.168.254.254 round-trip-time 1634 .RS 0 12 ttl-expired ip-4 126.96.36.199 round-trip-time 7609 .RS 0 13 ttl-expired ip-4 188.8.131.52 round-trip-time 8643 .RS 0 14 ttl-expired ip-4 184.108.40.206 round-trip-time 9755 .RS 0 15 ttl-expired ip-4 220.127.116.11 round-trip-time 10695 .RS 0 17 ttl-expired ip-4 18.104.22.168 round-trip-time 14077 .RS 0 16 ttl-expired ip-4 22.214.171.124 round-trip-time 15253 .RS 0 18 ttl-expired ip-4 126.96.36.199 round-trip-time 17080 .RS 0 19 reply ip-4 188.8.131.52 round-trip-time 17039 .RE 0 .LP Note that the replies in this example are printed out of order. (The reply to probe 17 arrives prior to the reply to probe 16.) This is the reason that it is important to send commands with unique token values, and to use those token values to match replies with their originating commands. .SH CONTACT INFORMATION .PP For the latest version, see the mtr web page at .UR http://\:www.\:bitwizard.\:nl/\:mtr/ .UE .PP For patches, bug reports, or feature requests, please open an issue on GitHub at: .UR https://\:github\:.com/\:traviscross/\:mtr .UE . .SH "SEE ALSO" .BR mtr (8), .BR icmp (7), .BR tcp (7), .BR udp (7), TCP/IP Illustrated (Stevens, ISBN 0201633469).