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traceroute - print the route packets take to network host
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]
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.
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 automatically. 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.
- Set the “Don’t Fragment” bit. This tells intermediate 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 should send
packets. By default, the interface is selected according to the
- -m max_hops
Specifies the maximum number of hops traceroute will probe. The
default value is 30.
- -N concurrent_hops
Specifies the number of probe packets sent out simultaneously.
Sending several probes concurrently can speed up traceroute considerably.
However, when specifying a number that’s too large,
the destination host will start to throw away random ICMP
responses (if it implements ICMP rate throttling), and tracer_oute
will be unable to detect the final hope reliably. The
default value is 6.
- Do not try to map IP addresses to host names when displaying
- -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 destination host, traceroute will not be able to identify
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
- -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
- 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.
- Set the loose source route option on outgoing packets, 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.
- -s source_addr
Chooses an alternative source address. Note that you must select
the address of one of the interfaces. By default, the address
of the outgoing interface is used.
- Print the version and exit.
Concept and command line options based on the original LBL implementation
of traceroute, written by Van Jacobson. This implentation is a
complete rewrite and redesign, written and copyright (C) 2000 Olaf
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