The need for traceroute and tracert tools
Digital networks are a constantly changing phenomena, which means, they require constant monitoring and reconfiguration if they are to be kept as efficient as possible. This means the administrators that are responsible for the upkeep of such networks require tools that help them make sense of what today, has become a complicated mash-up of digital highways connecting a cornucopia of gadgets that communicate using insanely-fast data transfer traffic. Their users, on the other hand, have come to expect reliable and fast connections whenever they log on to a network (local or otherwise).
These two common scenarios have created a demand for tools that help make all stakeholders happy. And among many such tools, there is one that can help with identifying connectivity and latency issues: the traceroute or tracert command.
- 1 The need for traceroute and tracert tools
- 2 What is traceroute or tracert?
- 3 The syntaxes
- 4 Screenshots of traceroute and tracert
- 5 How do tracert or traceroute work?
- 6 A little bit more about the TTL
- 7 How does traceroute or tracert help admins?
- 8 The 3 best tools for traceroute and tracert
- 9 Traceroute and tracert will draw the network for you
What is traceroute or tracert?
Traceroute and tracert are two commands that run tools used for network diagnostics and help with resolving connectivity issues by tracing the paths data packets take while traveling from their origins to their destinations.
On a Windows machine an admin would use the tracert command; while on a Linux or Mac OS one they would use the “traceroute” command instead. The syntaxes for the commands are:
tracert [-d] [-h maximum_hops] [-j host-list] [-w timeout] [-R] [-S srcaddr] [-4] [-6] target_name
traceroute [-46dFITUnreAV] [-f first_ttl] [-g gate,…] [-i device] [-m max_ttl] [-p port] [-s src_addr] [-q nqueries] [-N squeries] [-t tos] [-l flow_label] [-w waittimes] [-z sendwait] [-UL] [-D] [-P proto] [–sport=port] [-M method] [-O mod_options] [–mtu] [–back] host [packet_len]
Although the original tools were originally conceived to run from the CLIs (Command Line Interfaces), there are now more “flashier” versions with remarkable GUIs (Graphical User Interfaces). In this article, we will explore three of the best tools for traceroute and tracert.
Screenshots of traceroute and tracert
In the image below, the tracert command is running on a Windows machine and traces the path data packets would need to traverse if it had to reach the www.yahoo.com domain.
As we can see from the two images, once the command is executed, the program sends out a query across the network. This is to see which routes can be used to transport data packets between the origin machine’s network and the destination’s network.
Trivia: A tracert command from a Windows operating system machine sends out an ICMP (Internet Control Message Protocol) echo request, while a traceroute command from a Linux (or Mac) machine uses the UDP (User Datagram Protocol). The response, however, is always sent back in ICMP, regardless of what the sending host’s operating system is.
How do tracert or traceroute work?
To see how traceroute/tracert works, let us take a look at a breakdown of what occurs once a tracert or traceroute command has been sent:
- The command sends a packet out to the target device or network and starts monitoring for reports that are sent back in the form of replies from connected intermediary devices like routers and switches.
- The packets “hop” around from one device to the next and send back replies that help figure out their round-trip-times (RTTs). RTT is defined as the length of time taken for a packet to be sent out and then for a reply to come back confirming it has reached its intended destination.
- Whenever the packets hit a device and bounce back a reply, the admin also gets a bit of information detailing its IP address and device name (if it has one).
- Every time a packet is sent out, it is assigned a TTL (Time to Live) value that defaults to a maximum of 30 hops (but can be changed at will). We can see the advantages of the TTL by looking at what happens as the packet travels or hops across the network:
Step 1: When the first packet is sent out it is assigned a TTL of 1. When it reaches the first network device the TTL is reduced by 1 (making it 0 and hence dropping the packet) and a response is sent back to the source. This returning message will close a transport cycle allowing for the RTT to be calculated. If the replying device was the intended target, then the process ends with a “Resolved” message. If not…
Step 2: A second packet will then be sent with a TTL of 2. It passes through the device identified in Step 1 (where it loses a TTL value) and moves on to the next connected device beyond it. When it reaches a second device, it drops a TTL (making it 0) and a reply is sent back to the original host.
Step … n: The packets keep going out with increasing TTL values (until the maximum is reached) and the replies keep returning with a little more detail about the network that connects the origin and destination hosts.
Step “maximum no. of hops”: Finally, when the packet with the maximum number of hops is sent out, one of two things can be expected:
- Either, the destination host is reached and the network path is resolved or,
- The last packet will lose its TTL value, get dropped, and end with a “maximum number of hops reached” error message indicating the host couldn’t be reached.
A little bit more about the TTL
The TTL value determines the number of intermediate routers or other connecting devices that are going to be traversed as the packet travels towards the destination host. The traceroute/tracert command launches packets with TTL values starting at 1 and gradually increasing with each subsequent outgoing packet.
The TTL values decrease every time the packet hops to a device. Any packet whose TTL value reaches zero, is discarded and a “Time Exceeded” ICMP error message is generated and sent back to the original host.
Proceeding in this way, the tool uses the packets and reply messages to build a list of routers that data has to traverse through, until the destination is reached and returns an “ICMP Echo Reply” message.
How does traceroute or tracert help admins?
Once the network path has been mapped out, a network admin can simply look at it, follow the paths that were taken by consecutive packets. They can see for themselves where the problem is (in case of non-delivery of the packets) or that everything works just as well as it should.
Then, all that remains is to fix disconnected routers and tweaking the ones that have a high latency or packet loss rate.
The 3 best tools for traceroute and tracert
Now that we have an idea of how they work, let’s have a look at the three most efficient tracert or traceroute tools that every administrator can use to ensure they have a well-performing network.
- SolarWinds Traceroute NG (FREE TOOL)
- Path Analyzer Pro
SolarWinds is one of the biggest players in the network performance monitoring market. They are the makers of some impressive tools including the Traceroute NG – an easy-to-use, yet efficient network connection monitoring tool.
Traceroute NG – the tool that makes it all clear
With Traceroute NG, an administrator would have access to accurate single-path analysis visibility via CLI from the source to the destination hosts. It would effectively identify the number of hops, respective IP addresses, hostnames, packet loss, and latency.
- It detects path changes and gives due notification
- The tool allows for continuous probing that yields an iteration number for the user
- Both IPv4 and IPv6 networks are supported and can be analyzed
- The path number and trace information can be saved in a .txt log file
- It is easy to copy data from the tool’s GUI to the clipboard
- The “switch” command allows admins to alternate the probe type between ICMP and TCP
- It allows for simultaneous logging (via the logging command) as well as probing
- DNS lookup can be enabled or disabled
SolarWinds Traceroute NG is a FREE TOOL and can be downloaded at Solarwinds.com
For network administrators looking for an exciting little tool that can perform as well as any of the more complex traceroute tools out there, they will certainly find it all in VisualRoute. This network tool is a joy to use as its GUI makes work a lot of fun.
VisualRoute – reporting and diagnostics at its best
Administrators can get analytics results and reports that give advice like, “In general this route offers a good throughput, with hops responding on average within 68ms. However, all hops after hop 12 in network ‘[Network for 220.127.116.11]’ respond slightly slower than average.”
- A graphical map of the traceroute result makes it easy to comprehend and consume the data.
- Although VisualRoute’s main purpose is to map network paths, it goes above and beyond to perform several other essential network diagnostics with more tools like:
- Reverse tracing with remote agents so admins perform a reverse trace between two locations without actually being in either of the locations.
- Reverse DNS lookup allows to for the discovery of IP addresses behind a domain name.
- Ping plotting to gauge and capture response times of IP addresses over a given time and have the data available in informative graphs.
- Storage of tracert data for future reference and performance comparison.
- Sending out of continuous tracert commands over measured time intervals makes it easy for admins to monitor any performance degradations that could occur over time.
3. Path Analyzer Pro
Path Analyzer Pro is a traceroute tool that administrators with Mac machines can use alongside their Windows brethren as it works on both platforms. It is an amalgamation of tools that, apart from the main traceroute purpose, offers features that help with performance testing, DNS, Whois, and address resolution features.
Path Analyzer Pro – simple yet impressively efficient
Some of the features that admins can expect from their Path Analyzer Pro include:
- A concise and to-the-point GUI that even novices can easily master.
- Excellent time performance that sees admins getting results back 20 times faster.
- Elaborate, yet comprehensible, reports that can either be consumed on the platform or exported for other remote users. They have impressive graphics detailing every aspect of a network.
- Map-based location of IP addresses with zoom, pan, and details.
- E-mail address tracing that can be used by crime stoppers and fighters to dig up more details about spammers or senders of unsolicited email messages
Traceroute and tracert will draw the network for you
If you are a network administrator, then you will truly appreciate the capabilities of the three best traceroute and tracert tools we have just seen. Using one or all of them will allow you to draw an accurate picture of your network and the connectivity that lies beyond it. Make use of the tools and you will always have a clear image of what your network looks like.