The first ports of call when troubleshooting network latency or connectivity problems are usually traceroute and ping for managed services providers (MSPs), IT administrators, and technicians.
It is a simple testing process that can be run by anyone with access to a command prompt. However, understanding the test results can be difficult if you are unfamiliar with the traceroute’s basics. In this post, we are going to explain everything about traceroute including why and how how to run it.
Traceroute runs tools that perform network diagnostics. The purpose of these tools is to trace the path data packets take from their source to their destination, enabling administrators to resolve connectivity issues better. Tracert is the command on a Windows device; traceroute is the command on Linux and Mac devices.
The main difference between traceroute and tracert is how they map the route data takes from one point in a network to another. To transmit data between two points, it must pass through several devices, such as switches and routers. In addition to providing details and round-trip time (RTT), Traceroute shows the name and IP address of devices at each hop.
A traceroute can help you pinpoint the location of the problem, while a ping can indicate a problem. If you visit a website with slow-loading pages, you might use traceroute to discover where the problem lies. If this is the case, you can use traceroute to determine the route of the issue by determining where the most extended delays are occurring.
To run a traceroute command successfully, you should be familiar with the “time to live” (TTL). TTL limits how long data can “live” in an IP network. A TTL value is assigned to every packet of data. Each time a packet reaches a hop, its TTL value decreases by one.
Another critical element to understand is “round-trip time” (RTT). As part of the traceroute algorithm, every hop on the way to a destination device drops packets and sends an error ICMP message back. By measuring the time between sending the data and receiving the ICMP message, the traceroute is able to give you each hop’s RTT value.
We will use the example of running a traceroute with a maximum of 30 hops to illustrate this. To reach the destination server, Traceroute sends packets with one TTL. After passing through the first network device, the TTL value will decrease to zero, and a message will appear notifying you that the packets have been dropped. Using this method, you can determine the RTT for the first hop.
Afterwards, the data packets are sent to the destination server with a two-second TTL. Once the packets have passed through the first hop, the TTL drops to one. The value is zero as soon as they pass through the second hop. The message is sent again. This gives you the RTT for hop number two.
Data packets will be repeated until the destination device is reached or the maximum number of hops is reached. Once this test is complete, you will know the number of hops to the destination device, the RTT length for each hop, and the device name and IP address for each hop.
You can also use an online tool like the one provided by DNSChecker to run a traceroute test for a domain or IP.
There may be slight differences in traceroute results depending on the specific tool that you use.
If you use tracert, the Windows traceroute command will show the number of hops from the source device to the destination device in the far-left column.
The TRACERT tool sends three data packets to test each hop, so you’ll see three RTT values for each hop (using the default settings). More device information should be displayed on the right.
As a general rule, most people run a traceroute just for the sake of interest, which is the most common reason. Traceroute is a command that is used to determine the path between two network resources or connections in order to establish connectivity. Connecting to another device sometimes requires passing through multiple routers (hops). In the traceroute command, all routers between two connections are listed with their IP addresses.
Anyone who wishes to diagnose connectivity problems over a public network will need to know how to use the traceroute command. In spite of the fact that it isn’t complex, it does take some getting used to. It will provide essential knowledge for those working in the IT industry to experiment with the various traceroute options and learn how to interpret the results generated by this command.
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