mtr (8)

NAME

mtr - a network diagnostic tool

SYNOPSIS

mtr [-4|-6] [-F FILENAME] [--report] [--report-wide] [--xml] [--gtk] [--curses] [--raw] [--csv] [--split] [--no-dns] [--show-ips] [-o FIELDS] [-y IPINFO] [--aslookup] [-i INTERVAL] [-c COUNT] [-s PACKETSIZE] [-B BITPATTERN] [-Q TOS] [--mpls] [-a ADDRESS] [-f FIRST-TTL] [-m MAX-TTL] [--udp] [--tcp] [-P PORT] [-Z TIMEOUT] [-M MARK] HOSTNAME

DESCRIPTION

mtr combines the functionality of the traceroute and ping programs in a single network diagnostic tool.

As mtr starts, it investigates the network connection between the host mtr runs on and 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 mtr to print the response percentage and response times of the internet route to HOSTNAME. A sudden increase in packet loss or response time is often an indication of a bad (or simply overloaded) link.

The results are usually reported as round-trip-response times in miliseconds and the percentage of packetloss.

OPTIONS

-h, --help

Print the summary of command line argument options.

-v, --version

Print the installed version of mtr.

-4

Use IPv4 only.

-6

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

-F FILENAME, --filename FILENAME

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-r, --report

This option puts mtr into report mode. When in this mode, mtr will run for the number of cycles specified by the -c option, and then print statistics and exit.

This mode is useful for generating statistics about network quality. Note that each running instance of mtr generates a significant amount of network traffic. Using mtr to measure the quality of your network may result in decreased network performance.

-w, --report-wide

This option puts mtr into wide report mode. When in this mode, mtr will not cut hostnames in the report.

-x, --xml

Use this option to tell mtr to use the xml output format. This format is better suited for automated processing of the measurement results.

-t, --curses

Use this option to force mtr to use the curses based terminal interface (if available).

-g, --gtk

Use this option to force mtr to use the GTK+ based X11 window interface (if available). GTK+ must have been available on the system when mtr was built for this to work. See the GTK+ web page at www.gtk.org for more information about GTK+.

-l, --raw

Use this option to tell mtr to 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.

-C, --csv

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-p, --split

Use this option to set mtr to spit out a format that is suitable for a split-user interface.

-n, --no-dns

Use this option to force mtr to display numeric IP numbers and not try to resolve the host names.

-b, --show-ips

Use this option to tell 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.

-o FIELDS, --order FIELDS

Use this option to specify which fields to display and in which order. You may use one or more space characters to separate fields.
Available fields:

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

Example: -o "LSD NBAW X"

-y n, --ipinfo n

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-z, --aslookup

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-i SECONDS, --interval SECONDS

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.

-c COUNT, --report-cycles COUNT

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.

-s PACKETSIZE, --psize PACKETSIZE

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.

-B NUM, --bitpattern NUM

Specifies bit pattern to use in payload. Should be within range 0 - 255. If NUM is greater than 255, a random pattern is used.

-Q NUM, --tos NUM

Specifies value for type of service field in IP header. Should be within range 0 - 255.

-e, --mpls

Use this option to tell mtr to display information from ICMP extensions for MPLS (RFC 4950) that are encoded in the response packets.

-a ADDRESS, --address ADDRESS

Use this option to bind the outgoing socket to ADDRESS, so that all packets will be sent with ADDRESS as source address. NOTE that this option doesn't apply to DNS requests (which could be and could not be what you want).

-f NUM, --first-ttl NUM

Specifies with what TTL to start. Defaults to 1.

-m NUM, --max-ttl NUM

Specifies the maximum number of hops (max time-to-live value) traceroute will probe. Default is 30.

-u, --udp

Use UDP datagrams instead of ICMP ECHO.

-T, --tcp

Use TCP SYN packets instead of ICMP ECHO. PACKETSIZE is ignored, since SYN packets can not contain data.

-P PORT, --port PORT

The target port number for TCP traces.

-Z SECONDS, --timeout SECONDS

The number of seconds to keep the TCP socket open before giving up on the connection. This will only affect the final hop. Using large values for this, especially combined with a short interval, will use up a lot of file descriptors.

-M MARK, --mark MARK

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ENVIRONMENT

mtr recognizes a few environment variables.

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 MTR_OPTIONS are overriden by command-line options.
Example:
MTR_OPTIONS=-4 -c 1 mtr -6 localhost
would send one probe (because of -c 1) towards ::1 (because of -6, which overrides the -4 passed in MTR_OPTIONS).

DISPLAY

Used for the GTK+ frontend.

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 mtr will be significantly lower than the actual reliability of these routers.

CONTACT INFORMATION

For the latest version, see the mtr web page at www.bitwizard.nl/mtr.

The mtr mailinglist was little used and is no longer active.

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

SEE ALSO

traceroute(8), ping(8) TCP/IP Illustrated (Stevens, ISBN 0201633469).