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 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.
-F
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 routing table.
-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
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
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 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 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.
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 Kirch <okir@suse.de>.
