Traceroute Online is a tool that shows you the network path between two network
nodes (also called "hops"). It is commonly used for diagnostics of network
problems and it is useful for getting information about the network topology. A
round-trip time
is measured and reported for each node on the path from the source machine
to the target machine.
Traceroute Online works over the
Internet Control Message Protocol
(ICMP) by sending ICMP Echo Request packets. In general, however,
traceroute command can also be implemented using other protocols such as
User Datagram Protocol.
Traceroute works by increasing the
Time To Live (TTL)
value of packets it sends. The first set of packets is
sent with TTL set to 1. Each router on the network path decreases the TTL value
of each packet by 1 before it is sent to the next hop. When the TTL value of the
packet hits zero the packet is no longer forwarded and the source machine is
informed about this with ICMP Time Exceeded message. It is thus expected that
the first router in the network path will send Time Exceeded message when it
receives the first set of packets. The second set of packets is sent with TTL
set to 2 and so they are stopped by the second router in the network path etc.
When the TTL value is big enough to reach the target host, it replies to the
request and the whole process ends. Traceroute Online sends three packets with
the same TTL value before increasing it.
On the output Traceroute Online lists all the intermediate routers a network
packet must pass through to reach the target address. The round-trip time
statistics are also displayed for each node on the network path.
When a network node does not respond to Traceroute Online packets it might be a
sign of its network hardware failure, incorrect router or firewall
configuration, as well as a result of intentional configuration of the target
host's firewall not to response to Echo Request messages. In case of machines
connected to the Internet such a policy that forbids to reply to traceroute
packets is not rare. On the other hand, in the local network environments the
responsiveness is usually required.
To use Traceroute Online you just need to specify the target host name or IP
address in the Host / IP address field. By default the target
IP address is set to your IP address, which means that our server will try to
find a network path to your machine. Then click the "Trace!" button to start.
When you specify the host name, it will be translated to IP address before the
first packets are sent.
You can also set some other parameters of the traceroute command:
- Resolve addresses – Enables resolving IP addresses to hostnames.
- Maximum hops – The maximum number of hops on the path. If the network path to
the target host is longer than this limit, the result will contain information
about the first specified number of network nodes only.
- Timeout – Specifies the number of milliseconds to wait for each reply.
The maximal permitted duration of traceroute is 900 seconds. Since there
are always three packets with the same TTL value sent, this limit means
that 3*Timeout*Maximum hops should not exceed 900000.
