traceroute
SYNOPSIS
traceroute [-46FnrRV] [-f first_ttl] [-p port]
[-m max_hops] [-N concurrent_hops]
[-t tos] [-w timeout] [-q nqueries]
[-S source_addr] [-I interface]
[-g gateway] host [packetlen]
traceroute6 [options]
DESCRIPTION
traceroute tracks the route packets take across a TCP/IP
network on their way to a given host. It utilizes the IP
protocol's time to live (TTL) field and attempts to elicit
an ICMP TIME_EXCEEDED response from each gateway along the
path to the host.
traceroute6 is just another name for the same program, and
is equivalent to invoking traceroute with the -6 option.
OPTIONS
The only required parameter is the name or IP address of
the destination host. This paremeter can be followed by
the size of the probing packet sent to that host (40 by
default). Varying the size of the packet in conjunction
with the -F parameter can be used to obtain information
about the MTU of individual network hops.
Additional options are:
-6, -4 Explicitly force IPv4 or IPv6 traceouting. By
default, the program will try to resolve the name
given, and choose the appropriate protocol automat
ically. If resolving a host name returns both IPv4
and IPv6 addresses, traceroute will use IPv4.
Invoking the program as traceroute6 is the same as
using the -6 option.
-F Set the "Don't Fragment" bit. This tells intermedi
ate routers not to fragment the packet when they
find it's too big for a network hop's MTU.
-f first_ttl
Specifies with what TTL to start. Defaults to 1.
-g gateway
Tells traceroute to add an IP source routing option
to the outgoing packet that tells the network to
route the packet through the specified gateway.
Not very useful, because most routers have disabled
source routing for security reasons.
-I interface
Specifies the interface through which to traceroute
throttling), and traceroute will be unable to
detect the final hope reliably. The default value
is 6.
-n Do not try to map IP addresses to host names when
displaying them.
-p port
Specifies the UDP destination port base traceroute
will use. When sending its UDP probe packets, it
will send them to port + hop - 1 for each hop. If
there are ports in this range in use on the desti
nation host, traceroute will not be able to iden
tify reliably when it has reached the destination
host (probes will appear to time out). The default
port is 33434; you can use -p to change this to a
different value.
-t tos Set the IP Type of Service (TOS) and Precedence
value. Useful values are 16 (low delay) and 8 (high
throughput). Note that in order to use some TOS
precendence values, you have to be super user.
-w sec Wait for sec seconds before sending the next probe
packet.
Note that unlike older traceroute versions, this
implementation will transmit several probe packets
in parallel, for different hop values. However, it
will never send more than 1 packet per hop value at
the same time.
-q numqueries
Sets the number of probe packets per hop. The
default value is 3.
-r Bypass the normal routing tables and send directly
to a host on an attached network. If the host is
not on a directly-attached network, an error is
returned. This option can be used to ping a local
host through an interface that has no route through
it.
-R Set the loose source route option on outgoing pack
ets, asking intermediate routers to record their
address as the packet passes. This can be useful
if you want to find the address of an intermediate
router that has been configured to not respond to
traceroute packets.
This feature hasn't been implemented yet.
This implentation is a complete rewrite and redesign,
written and copyright (C) 2000 Olaf Kirch
<okir@caldera.de>.
6 December 2000 TRACEROUTE(1)
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