.TH MTR 8 "@VERSION@" "mtr" "System Administration"

.SH NAME

mtr \- a network diagnostic tool

.SH SYNOPSIS

.B mtr

[\c

.BR \-4 |\c

.B \-6\c

]

[\c

.BI \-F \ FILENAME\c

]

[\c

.B \-\-report\c

]

[\c

.B \-\-report-wide\c

]

[\c

.B \-\-xml\c

]

[\c

.B \-\-gtk\c

]

[\c

.B \-\-curses\c

]

[\c

.BI \--displaymode \ MODE\c

]

[\c

.B \-\-raw\c

]

[\c

.B \-\-csv\c

]

[\c

.B \-\-json\c

]

[\c

.B \-\-split\c

]

[\c

.B \-\-no-dns\c

]

[\c

.B \-\-show-ips\c

]

[\c

.BI \-o \ FIELDS\c

]

[\c

.BI \-y \ IPINFO\c

]

[\c

.B \-\-aslookup\c

]

[\c

.BI \-i \ INTERVAL\c

]

[\c

.BI \-c \ COUNT\c

]

[\c

.BI \-s \ PACKETSIZE\c

]

[\c

.BI \-B \ BITPATTERN\c

]

[\c

.BI \-G \ GRACEPERIOD\c

]

[\c

.BI \-Q \ TOS\c

]

[\c

.B \-\-mpls\c

]

[\c

.BI \-a \ ADDRESS\c

]

[\c

.BI \-f \ FIRST\-TTL\c

]

[\c

.BI \-m \ MAX\-TTL\c

]

[\c

.BI \-U \ MAX\-UNKNOWN\c

]

[\c

.B \-\-udp\c

]

[\c

.B \-\-tcp\c

]

[\c

.BI \-\-sctp\c

]

[\c

.BI \-P \ PORT\c

]

[\c

.BI \-L \ LOCALPORT\c

]

[\c

.BI \-Z \ TIMEOUT\c

]

[\c

.BI \-M \ MARK\c

]

.I HOSTNAME

.SH DESCRIPTION

.B mtr 

combines the functionality of the 

.B traceroute

and 

.B ping

programs in a single network diagnostic tool.

.PP

As 

.B mtr 

starts, it investigates the network connection between the host 

.B mtr

runs on and 

.BR HOSTNAME

by sending packets with purposely low TTLs.  It continues to send

packets with low TTL, noting the response time of the intervening

routers.  This allows 

.B mtr 

to print the response percentage and response times of the internet

route to 

.BR HOSTNAME . 

A sudden increase in packet loss or response time is often an indication

of a bad (or simply overloaded) link. 

.PP

The results are usually reported as round-trip-response times in milliseconds

and the percentage of packetloss. 

.SH OPTIONS

.TP

.B \-h\fR, \fB\-\-help

Print the summary of command line argument options.

.TP

.B \-v\fR, \fB\-\-version

Print the installed version of mtr.  

.TP

.B \-4

Use IPv4 only.

.TP

.B \-6

Use IPv6 only.  (IPV4 may be used for DNS lookups.)

.TP

.B \-F \fIFILENAME\fR, \fB\-\-filename \fIFILENAME

Reads the list of hostnames from the specified file.

.TP

.B \-r\fR, \fB\-\-report

This option puts 

.B mtr

into 

.B report

mode.  When in this mode,

.B mtr

will run for the number of cycles specified by the 

.B \-c

option, and then print statistics and exit.  

.TP

\c

This mode is useful for generating statistics about network quality.  

Note that each running instance of 

.B mtr

generates a significant amount of network traffic.  Using 

.B mtr

to measure the quality of your network may result in decreased

network performance.  

.TP

.B \-w\fR, \fB\-\-report\-wide

This option puts 

.B mtr

into 

.B wide report

mode.  When in this mode,

.B mtr

will not cut hostnames in the report. 

.TP

.B \-x\fR, \fB\-\-xml

Use this option to tell

.B mtr

to use the xml output format.  This format is better suited for

automated processing of the measurement results.

.TP

.B \-t\fR, \fB\-\-curses

Use this option to force 

.B mtr 

to use the curses based terminal

interface (if available).

In case the list of hops exceeds the 

height of your terminal, you can use the 

.B +

and

.B -

keys to scroll up and down half a page.

.B Ctrl\fR-\fPL

clears spurious error messages that may overwrite other parts of the display.

.TP

.B -\-displaymode \fIMODE

Use this option to select the initial display mode: 0 (default)

selects statistics, 1 selects the stripchart without latency

information, and 2 selects the stripchart with latency

information.

.TP

.B \-g\fR, \fB\-\-gtk

Use this option to force

.B mtr 

to use the GTK+ based X11 window interface (if available).  

GTK+ must have been available on the system when 

.B mtr 

was built for this to work.  See the GTK+ web page at 

.UR http://\:www.\:gtk.\:org/

.UE

for more information about GTK+.

.TP

.B \-l\fR, \fB\-\-raw

Use the raw output format.  This format is better suited for

archival of the measurement results.  It could be parsed to 

be presented into any of the other display methods. 

.IP

Example of the raw output format:

.nf

h 0 10.1.1.1

p 0 339

h 1 46.149.16.4

p 1 530

h 2 172.31.1.16

p 2 531

h 3 82.221.168.236

p 3 1523

h 5 195.130.211.8

p 5 1603

h 6 193.4.58.17

p 6 1127

h 7 193.4.58.17

d 7 www.isnic.is

.fi

.TP

.B \-C\fR, \fB\-\-csv

Use the Comma-Separated-Value (CSV) output format.

(Note: The separator is actually a semi-colon ';'.)

.IP

Example of the CSV output format:

.nf

MTR.0.86+git:16e39fc0;1435562787;OK;nic.is;1;r-76520-PROD.greenqloud.internal;288

MTR.0.86+git:16e39fc0;1435562787;OK;nic.is;2;46.149.16.4;2086

MTR.0.86+git:16e39fc0;1435562787;OK;nic.is;3;172.31.1.16;600

MTR.0.86+git:16e39fc0;1435562787;OK;nic.is;4;82.221.168.236;1163

MTR.0.86+git:16e39fc0;1435562787;OK;nic.is;5;???;0

MTR.0.86+git:16e39fc0;1435562787;OK;nic.is;6;rix-k2-gw.isnic.is;1654

MTR.0.86+git:16e39fc0;1435562787;OK;nic.is;7;www.isnic.is;1036

.fi

.TP

.B \-j\fR, \fB\-\-json

Use this option to tell

.B mtr

to use the JSON output format.  This format is better suited for

automated processing of the measurement results.

.TP

.B \-p\fR, \fB\-\-split

Use this option to set

.B mtr 

to spit out a format that is suitable for a split-user interface.

.TP

.B \-n\fR, \fB\-\-no\-dns

Use this option to force 

.B mtr 

to display numeric IP numbers and not try to resolve the

host names. 

.TP

.B \-b\fR, \fB\-\-show\-ips

Use this option to tell

.B mtr

to display both the host names and numeric IP numbers.  In split mode

this adds an extra field to the output.  In report mode, there is usually

too little space to add the IPs, and they will be truncated.  Use the

wide report (-w) mode to see the IPs in report mode. 

.TP

.B \-o \fIFIELDS\fR, \fB\-\-order \fIFIELDS

Use this option to specify which fields to display and in which order.

You may use one or more space characters to separate fields.

.br

Available fields:

.TS

center allbox tab(%);

ll.

L%Loss ratio

D%Dropped packets

R%Received packets

S%Sent Packets

N%Newest RTT(ms)

B%Min/Best RTT(ms)

A%Average RTT(ms)

W%Max/Worst RTT(ms)

V%Standard Deviation

G%Geometric Mean

J%Current Jitter

M%Jitter Mean/Avg.

X%Worst Jitter

I%Interarrival Jitter

.TE

.br

Example:

-o "LSD NBAW  X"

.TP

.B \-y \fIn\fR, \fB\-\-ipinfo \fIn

Displays information about each IP hop.  Valid values for \fIn\fR are:

.TS

tab(%);

ll.

0%Display AS number (equivalent to \fB-z\fR)

1%Display IP prefix

2%Display country code of the origin AS

3%Display RIR (ripencc, arin, ...)

4%Display the allocation date of the IP prefix

.TE

.br

It is possible to cycle between these fields at runtime (using the \fBy\fR key).

.TP

.B \-z\fR, \fB\-\-aslookup

Displays the Autonomous System (AS) number alongside each hop.  Equivalent to \fB\-\-ipinfo 0\fR.

.IP

Example (columns to the right not shown for clarity):

.nf

1. AS???   r-76520-PROD.greenqloud.internal

2. AS51969 46.149.16.4

3. AS???   172.31.1.16

4. AS30818 82.221.168.236

5. ???

6. AS???   rix-k2-gw.isnic.is

7. AS1850  www.isnic.is

.fi

.TP

.B \-i \fISECONDS\fR, \fB\-\-interval \fISECONDS

Use this option to specify the positive number of seconds between ICMP

ECHO requests.  The default value for this parameter is one second.  The

root user may choose values between zero and one.

.TP

.B \-c \fICOUNT\fR, \fB\-\-report\-cycles \fICOUNT

Use this option to set the number of pings sent to determine

both the machines on the network and the reliability of 

those machines.  Each cycle lasts one second.

.TP

.B \-s \fIPACKETSIZE\fR, \fB\-\-psize \fIPACKETSIZE

This option sets the packet size used for probing.  It is in bytes,

inclusive IP and ICMP headers.

If set to a negative number, every iteration will use a different, random

packet size up to that number.

.TP

.B \-B \fINUM\fR, \fB\-\-bitpattern \fINUM

Specifies bit pattern to use in payload.  Should be within range 0 - 255.  If

.I NUM

is greater than 255, a random pattern is used.

.TP

.B \-G \fISECONDS\fR, \fB\-\-gracetime \fISECONDS

Use this option to specify the positive number of seconds to wait for responses

after the final request. The default value is five seconds.

.TP

.B \-Q \fINUM\fR, \fB\-\-tos \fINUM

Specifies value for type of service field in IP header.  Should be within range 0

- 255.

.TP

.B \-e\fR, \fB\-\-mpls

Use this option to tell 

.B mtr 

to display information from ICMP extensions for MPLS (RFC 4950)

that are encoded in the response packets.

.TP

.B \-a \fIADDRESS\fR, \fB\-\-address \fIADDRESS

Use this option to bind the outgoing socket to

.IR ADDRESS ,

so that all packets will be sent with

.I ADDRESS

as source address.  NOTE that this option doesn't apply to DNS requests

(which could be and could not be what you want).

.TP

.B \-f \fINUM\fR, \fB\-\-first-ttl \fINUM

Specifies with what TTL to start.  Defaults to 1.

.TP

.B \-m \fINUM\fR, \fB\-\-max-ttl \fINUM

Specifies the maximum number of hops (max time-to-live value) traceroute will

probe.  Default is 30.

.TP

.B \-U \fINUM\fR, \fB\-\-max-unknown \fINUM

Specifies the maximum unknown host. Default is 5.

.TP

.B \-u\fR, \fB\-\-udp

Use UDP datagrams instead of ICMP ECHO.

.TP

.B \-T\fR, \fB\-\-tcp

Use TCP SYN packets instead of ICMP ECHO.

.I PACKETSIZE

is ignored, since SYN packets can not contain data.

.TP

.B \-S\fR, \fB\-\-sctp

Use Stream Control Transmission Protocol packets instead of ICMP ECHO.

.TP

.B \-P \fIPORT\fR, \fB\-\-port \fIPORT

The target port number for TCP/SCTP/UDP traces.

.TP

.B \-L \fILOCALPORT\fR, \fB\-\-localport \fILOCALPORT

The source port number for UDP traces.

.TP

.B \-Z \fISECONDS\fR, \fB\-\-timeout \fISECONDS

The number of seconds to keep probe sockets open before giving up on

the connection.  Using large values for this, especially combined with

a short interval, will use up a lot of file descriptors.

.TP

.B \-M \fIMARK\fR, \fB\-\-mark \fIMARK

Set the mark for each packet sent through this socket similar to the

netfilter MARK target but socket-based.

.I MARK

is 32 unsigned integer.  See

.BR socket (7)

for full description of this socket option.

.SH ENVIRONMENT

.B mtr

recognizes a few environment variables.

.TP

.B MTR_OPTIONS

This environment variable allows to specify options, as if they were

passed on the command line.  It is parsed before reading the actual

command line options, so that options specified in

.B MTR_OPTIONS

are overridden by command-line options.

Example:

.BI MTR_OPTIONS ="-4\ -c\ 1"

.B mtr

.I \-6\ localhost

would send one probe (because of

.I -c\ 1\c

) towards

.B ::1

(because of

.IR -6 ,

which overrides the

.I -4

passed in

.B MTR_OPTIONS\c

).

.TP

.B MTR_PACKET

A path to the

.I mtr-packet

executable, to be used for sending and receiving network probes.  If

.B MTR_PACKET

is unset, the

.B PATH

will be used to search for an

.I mtr-packet

executable.

.TP

.B DISPLAY

Specifies an X11 server for the GTK+ frontend.

.SH BUGS

Some modern routers give a lower priority to ICMP ECHO packets than 

to other network traffic.  Consequently, the reliability of these

routers reported by 

.B mtr

will be significantly lower than the actual reliability of 

these routers.  

.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-packet (8),

.BR traceroute (8),

.BR ping (8),

.BR socket (7),

TCP/IP Illustrated (Stevens, ISBN 0201633469).