mtr.8

.TH MTR 8 "March 4, 1999" "mtr" "mtr"


.SH NAME
mtr \- a network diagnostic tool


.SH SYNOPSIS
.B mtr 
[\c
.B \-hvrctglspeniu46\c
]
[\c
.B \-\-help\c
]
[\c
.B \-\-version\c
]
[\c
.B \-\-report\c
]
[\c
.B \-\-report-wide\c
]
[\c
.B \-\-report\-cycles\ COUNT\c
]
[\c
.B \-\-curses\c
]
[\c
.B \-\-split\c
]
[\c
.B \-\-raw\c
]
[\c
.B \-\-mpls\c
]
[\c
.B \-\-no-dns\c
]
[\c
.B \-\-show-ips\c
]
[\c
.B \-\-gtk\c
]
[\c
.B \-\-address\ IP.ADD.RE.SS\c
]
[\c
.B \-\-interval\ SECONDS\c
]
[\c
.B \-\-psize\ BYTES | -s BYTES\c
]
.B HOSTNAME [PACKETSIZE]


.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 miliseconds 
and the percentage of packetloss. 

.SH OPTIONS

.TP
.B \-h
.TP
.B \-\-help
.br
Print the summary of command line argument options.

.TP
.B \-v
.TP
.B \-\-version
.br
Print the installed version of mtr.  

.TP
.B \-r
.TP
.B \-\-report
.br
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
.TP
.B \-\-report-wide
.br
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 \-c\ COUNT
.TP
.B \-\-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.

.TP
.B \-s\ BYTES
.TP
.B \-\-psize\ BYTES
.TP
.B PACKETSIZE
These options or a trailing PACKETSIZE on the command line 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 upto that number. 
.TP
.B \-t
.TP
.B \-\-curses
.br
Use this option to force 
.B mtr 
to use the curses based terminal
interface (if available).

.TP
.B \-e
.TP
.B \-\-mpls
.br
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 \-n
.TP
.B \-\-no-dns
.br
Use this option to force 
.B mtr 
to display numeric IP numbers and not try to resolve the
host names. 

.TP
.B \-b
.TP
.B \-\-show-ips
.br
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\ fields\ order
.TP
.B \-\-order\ fields\ order
.br
Use this option to specify the fields and their order when loading mtr.
.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"
.TP
.B \-g
.TP
.B \-\-gtk
.br
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 
.B http://www.gtk.org/
for more information about GTK+.

.TP
.B \-p
.TP
.B \-\-split
.br
Use this option to set
.B mtr 
to spit out a format that is suitable for a split-user interface.

.TP
.B \-l
.TP
.B \-\-raw
.br
Use this option to tell 
.B 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. 

.TP
.B \-a\ IP.ADD.RE.SS
.TP
.B \-\-address\ IP.ADD.RE.SS
.br
Use this option to bind outgoing packets' socket to specific interface,
so that any packet will be sent through this interface. NOTE that this
option doesn't apply to DNS requests (which could be and could not be 
what you want).

.TP
.B \-i\ SECONDS
.TP
.B \-\-interval\ SECONDS
.br
Use this option to specify the positive number of seconds between ICMP
ECHO requests.  The default value for this parameter is one second.

.TP
.B \-u
.br
Use UDP datagrams instead of ICMP ECHO.

.TP
.B \-4
.br
Use IPv4 only.

.TP
.B \-6
.br
Use IPv6 only.

.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 
.BR http://www.bitwizard.nl/mtr/ .

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

.PP
Bug reports and feature requests should be submitted to the
launchpad mtr bugtracker. 

.SH "SEE ALSO"

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