Tracert
Updated: January 21, 2005
Determines the path taken to a destination by sending
Internet Control Message Protocol (ICMP) Echo Request or
ICMPv6 messages to the destination with incrementally
increasing Time to Live (TTL) field values. The path
displayed is the list of near-side router interfaces of the
routers in the path between a source host and a destination.
The near-side interface is the interface of the router that
is closest to the sending host in the path. Used without
parameters, tracert displays help.
Syntax
tracert [-d] [-hMaximumHops] [-jHostList]
[-wTimeout] [-R] [-SSrcAddr]
[-4][-6] TargetName
Parameters
-d
Prevents tracert from attempting to
resolve the IP addresses of intermediate routers
to their names. This can speed up the display of
tracert results.
-hMaximumHops
Specifies the maximum number of hops in the path
to search for the target (destination). The
default is 30 hops.
-jHostList
Specifies that Echo Request messages use the
Loose Source Route option in the IP header with
the set of intermediate destinations specified
in HostList. With loose source routing,
successive intermediate destinations can be
separated by one or multiple routers. The
maximum number of addresses or names in the host
list is 9. The HostList is a series of IP
addresses (in dotted decimal notation) separated
by spaces. Use this parameter only when tracing
IPv4 addresses.
-wTimeout
Specifies the amount of time in milliseconds to
wait for the ICMP Time Exceeded or Echo Reply
message corresponding to a given Echo Request
message to be received. If not received within
the time-out, an asterisk (*) is displayed. The
default time-out is 4000 (4 seconds).
-R
Specifies that the IPv6 Routing extension header
be used to send an Echo Request message to the
local host, using the destination as an
intermediate destination and testing the reverse
route.
-S
Specifies the source address to use in the Echo
Request messages. Use this parameter only when
tracing IPv6 addresses.
-4
Specifies that Tracert.exe can use only IPv4 for
this trace.
-6
Specifies that Tracert.exe can use only IPv6 for
this trace.
TargetName
Specifies the destination, identified either by
IP address or host name.
-?
Displays help at the command prompt.
Remarks
- This diagnostic tool determines the path taken to a destination by sending ICMP Echo Request messages with varying Time to Live (TTL) values to the destination. Each router along the path is required to decrement the TTL in an IP packet by at least 1 before forwarding it. Effectively, the TTL is a maximum link counter. When the TTL on a packet reaches 0, the router is expected to return an ICMP Time Exceeded message to the source computer. Tracert determines the path by sending the first Echo Request message with a TTL of 1 and incrementing the TTL by 1 on each subsequent transmission until the target responds or the maximum number of hops is reached. The maximum number of hops is 30 by default and can be specified using the -h parameter. The path is determined by examining the ICMP Time Exceeded messages returned by intermediate routers and the Echo Reply message returned by the destination. However, some routers do not return Time Exceeded messages for packets with expired TTL values and are invisible to the tracert command. In this case, a row of asterisks (*) is displayed for that hop.
- To trace a path and provide network latency and packet loss for each router and link in the path, use the pathping command.
- This command is available only if the Internet Protocol (TCP/IP) protocol is installed as a component in the properties of a network adapter in Network Connections.
Examples
To trace the path to the host named corp7.microsoft.com,
type:
tracert corp7.microsoft.com
To trace the path to the host named corp7.microsoft.com and prevent the resolution of each IP address to its name, type:
tracert -d corp7.microsoft.com
To trace the path to the host named corp7.microsoft.com and use the loose source route 10.12.0.1-10.29.3.1-10.1.44.1, type:
tracert -j 10.12.0.1 10.29.3.1 10.1.44.1 corp7.microsoft.com
Formatting legend
| Format | Meaning |
| Italic | Information that the user must supply |
| Bold | Elements that the user must type exactly as shown |
| Ellipsis (...) | Parameter that can be repeated several times in a command line |
| Between brackets ([]) | Optional items |
| Between braces ({}); choices separated by pipe (|). Example: {even|odd} | Set of choices from which the user must choose only one |
| Courier font | Code or program output |