Tracert

• Tracert is a command-line utility that you can use to trace the path that an Internet Protocol (IP) packet takes to its destination.
• It also calculates and displays the amount of time each hop took.

Working process

• When you enter the tracert command, the utility initiates the sending of a packet using the Internet Control Message Protocol (ICMP).
• In these packets, tracert uses varying IP Time-To-Live (TTL) values. Because each router along the path is required to decrement the packet's TTL by at least 1 before forwarding the packet.
• When the TTL on a packet reaches 0, the router sends an ICMP "Request timed out" message back to the source computer.
• Tracert sends the first packet with a TTL of 1 and increments the TTL by 1 on each subsequent transmission until the destination respond.
• The ICMP "Request timed out" messages that intermediate routers send back show the route.
• However that some routers silently drop packets that have expired TTLs and these packets are invisible to tracert.





• Tracert prints out an ordered list of the intermediate routers that return ICMP "Request timed out" messages.

Tracert syntax

tracert [-d] [-h MaxHops] [-j HostList] [-w TimeOut] target [/?]

-d

• This option prevents tracert from resolving IP addresses to hostnames, often resulting in much faster results.

-h MaxHops

• It determine maximum number of hops in the search for the target.
• If you do not specify MaxHops, and target has not been found by 30 hops, tracert will stop looking.

-j HostList

• Specifies loose source route along the host-list.

-w TimeOut

• Waits the number of milliseconds specified by timeout for each reply.

target

• Specifies the name or IP address of the target host.

/?

• Use the help switch with the tracert command to show detailed help about the command's several options.