<s>
My	B-Protocol
traceroute	I-Protocol
,	O
originally	O
named	O
Matt	O
's	O
traceroute	B-Protocol
(	O
MTR	B-Protocol
)	O
,	O
is	O
a	O
computer	B-Application
program	I-Application
which	O
combines	O
the	O
functions	O
of	O
the	O
traceroute	B-Protocol
and	O
ping	B-Protocol
programs	O
in	O
one	O
network	O
diagnostic	O
tool	O
.	O
</s>
<s>
MTR	B-Protocol
probes	O
routers	B-Protocol
on	O
the	O
route	O
path	O
by	O
limiting	O
the	O
number	O
of	O
hops	O
individual	O
packets	B-Protocol
may	O
traverse	O
,	O
and	O
listening	O
to	O
responses	O
of	O
their	O
expiry	O
.	O
</s>
<s>
The	O
original	O
Matt	O
's	O
traceroute	B-Protocol
program	I-Protocol
was	O
written	O
by	O
Matt	O
Kimball	O
in	O
1997	O
.	O
</s>
<s>
Roger	O
Wolff	O
took	O
over	O
maintaining	O
MTR	B-Protocol
(	O
renamed	O
My	B-Protocol
traceroute	I-Protocol
)	O
in	O
October	O
1998	O
.	O
</s>
<s>
MTR	B-Protocol
is	O
licensed	O
under	O
the	O
terms	O
of	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
(	O
GPL	B-License
)	O
and	O
works	O
under	O
modern	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
It	O
normally	O
works	O
under	O
the	O
text	O
console	O
,	O
but	O
it	O
also	O
has	O
an	O
optional	O
GTK+	B-Application
-based	O
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
.	O
</s>
<s>
MTR	B-Protocol
relies	O
on	O
Internet	B-Protocol
Control	I-Protocol
Message	I-Protocol
Protocol	I-Protocol
(	O
ICMP	O
)	O
Time	O
Exceeded	O
(	O
type	O
11	O
,	O
code	O
0	O
)	O
packets	B-Protocol
coming	O
back	O
from	O
routers	B-Protocol
,	O
or	O
ICMP	B-Protocol
Echo	I-Protocol
Reply	I-Protocol
packets	B-Protocol
when	O
the	O
packets	B-Protocol
have	O
hit	O
their	O
destination	O
host	O
.	O
</s>
<s>
MTR	B-Protocol
also	O
has	O
a	O
User	B-Protocol
Datagram	I-Protocol
Protocol	I-Protocol
(	O
UDP	O
)	O
mode	O
(	O
invoked	O
with	O
"	O
-u	O
"	O
on	O
the	O
command	O
line	O
or	O
pressing	O
the	O
"	O
u	O
"	O
key	O
in	O
the	O
curses	O
interface	O
)	O
that	O
sends	O
UDP	B-Protocol
packets	I-Protocol
,	O
with	O
the	O
time	B-Protocol
to	I-Protocol
live	I-Protocol
(	O
TTL	O
)	O
field	O
in	O
the	O
IP	O
header	O
increasing	O
by	O
one	O
for	O
each	O
probe	O
sent	O
,	O
toward	O
the	O
destination	O
host	O
.	O
</s>
<s>
When	O
the	O
UDP	O
mode	O
is	O
used	O
,	O
MTR	B-Protocol
relies	O
on	O
ICMP	O
port	O
unreachable	O
packets	B-Protocol
(	O
type	O
3	O
,	O
code	O
3	O
)	O
when	O
the	O
destination	O
is	O
reached	O
.	O
</s>
<s>
MTR	B-Protocol
also	O
supports	O
IPv6	B-Protocol
and	O
works	O
in	O
a	O
similar	O
manner	O
but	O
instead	O
relies	O
on	O
ICMPv6	B-Protocol
messages	O
.	O
</s>
<s>
By	O
showing	O
a	O
list	O
of	O
routers	B-Protocol
traversed	O
,	O
and	O
the	O
average	O
round-trip	O
time	O
as	O
well	O
as	O
packet	B-Protocol
loss	I-Protocol
to	O
each	O
router	B-Protocol
,	O
it	O
allows	O
users	O
to	O
identify	O
links	O
between	O
two	O
given	O
routers	B-Protocol
responsible	O
for	O
certain	O
fractions	O
of	O
the	O
overall	O
latency	O
or	O
packet	B-Protocol
loss	I-Protocol
through	O
the	O
network	O
.	O
</s>
<s>
This	O
example	O
shows	O
MTR	B-Protocol
running	O
on	O
Linux	B-Application
tracing	O
a	O
route	O
from	O
the	O
host	O
machine	O
(	O
example.lan	O
)	O
to	O
a	O
web	B-Application
server	I-Application
at	O
Yahoo	B-Application
!	I-Application
</s>
<s>
(	O
p25.www.re2.yahoo.com	O
)	O
across	O
the	O
Level	O
3	O
Communications	O
network	O
.	O
</s>
<s>
An	O
additional	O
example	O
below	O
shows	O
a	O
recent	O
version	O
of	O
MTR	B-Protocol
running	O
on	O
FreeBSD	B-Operating_System
.	O
</s>
<s>
MPLS	B-Protocol
labels	O
are	O
displayed	O
by	O
default	O
when	O
the	O
"	O
-e	O
"	O
switch	O
is	O
used	O
on	O
the	O
command	O
line	O
(	O
or	O
the	O
"	O
e	O
"	O
key	O
is	O
pressed	O
in	O
the	O
curses	O
interface	O
)	O
:	O
</s>
<s>
WinMTR	B-Protocol
is	O
a	O
Windows	O
GUI	B-Application
application	O
functionally	O
equivalent	O
to	O
MTR	B-Protocol
.	O
</s>
<s>
Although	O
it	O
is	O
very	O
similar	O
,	O
WinMTR	B-Protocol
shares	O
no	O
common	O
code	O
with	O
MTR	B-Protocol
.	O
</s>
<s>
A	O
console	O
version	O
of	O
MTR	B-Protocol
does	O
exist	O
for	O
Windows	O
,	O
but	O
it	O
has	O
fewer	O
features	O
than	O
MTR	B-Protocol
on	O
other	O
platforms	O
.	O
</s>
<s>
Windows	B-Device
NT	I-Device
and	O
beyond	O
has	O
a	O
built-in	O
PathPing	B-Protocol
command	O
that	O
similarly	O
combines	O
the	O
functionality	O
of	O
ping	B-Protocol
with	O
that	O
of	O
tracert	B-Protocol
.	O
</s>
<s>
Because	O
it	O
displays	O
the	O
degree	O
of	O
packet	B-Protocol
loss	I-Protocol
at	O
any	O
given	O
router	B-Protocol
or	O
link	O
,	O
it	O
can	O
also	O
be	O
used	O
to	O
determine	O
which	O
routers	B-Protocol
or	O
subnets	O
might	O
be	O
having	O
network	O
problems	O
.	O
</s>
