Packet Loss: Identify the
source with PRTG

  • PRTG monitors traffic
  • PRTG monitors data packets
  • PRTG monitors hardware
  • PRTG uses packet sniffing, SNMP, NetFlow, and WMI
  • PRTG performs short and long-term analysis


The five most common questions regarding packet loss

How does packet loss occur?

How does packet loss occur?

Nowadays, networks in medium-sized and large companies are built in a complex fashion. Data is transported using specific protocols and a variety of different hubs. During transmission, data is constantly prone to network disturbances, and as a result, packet loss.

What are the consequences of packet loss?

What are the consequences of packet loss?

Packet loss is quickly discernible in the day-to-day functioning of any enterprise. If video conferencing or VoIP is down on a regular basis, then it won’t be long before employees start to complain. And these complaints must be resolved by IT.

How can I measure packet loss?

How can I measure packet loss?

In PRTG, a number of sensors display the data packet loss rate. In the event a critical value is exceeded, you’ll automatically receive an alert. You'll therefore be notified should packet loss reach a certain level – ideally, before your coworkers start to complain.

How can I reduce packet loss?

How can I reduce packet loss?

As an administrator, your job is to find out what is causing packet loss and eliminate the sources of errors. To do so, you must be able to measure, test, and eliminate packet loss. Some of the things you can do are increase bandwith or reduce the strain put on hardware.

What are some concrete things I can do right away?

What are some concrete things I can do right away?

You can start by treating UDP packets with priority to keep video and VoIP connections as unobstructed as possible. On the other hand, slight delays in downloads (e.g. via FTP) or emails (SMTP, POP3, IMAP) are less noticeable to employees and therefore not as crucial for ensuring smooth work operations.

Measuring packet loss with PRTG: Three sensors to get started


  • Use the PRTG Ping-Sensor to measure the availability of your devices and to calculate packet loss as a percentage.
  • The Quality of Service Sensor lets you monitor network paths, and thereby measure and reduce packet loss. This sensor is also included.
  • Use the Cisco IP SLA Sensor to measure the packet loss rate on your Cisco devices.

Packet loss:
What are the causes? And what can be done to stop it?



iWhat is a sensor?

In PRTG, “Sensors” are the basic monitoring elements. One sensor usually monitors one measured value in your network, e.g. the traffic of a switch port, the CPU load of a server, the free space of a disk drive. On average you need about 5-10 sensors per device or one sensor per switch port.

View video (4:34 min.)

Network overload

Cause 1: Network overload

As companies grow, so does their network traffic. More and more traffic flows across servers, routers, and switches. Overloads lead to transmission errors, which in turn result in packet loss.

Solution: PRTG monitors the traffic in your entire network. It allows you to detect short-turn load peaks as well as gradual increases in traffic. Sensor tip: Use bandwidth sensors such as SNMP Traffic, NetFlow, IPFIX, and others.

Device performance

Cause 2: Device performance

Overall, your network is extremely stable. But the CPUs of individual devices are overloaded and unable to fully process data. As a result, packet loss occurs. The bottleneck has a negative effect on your entire network.

Solution: Use PRTG to monitor all the hardware in your network. By doing so, you’ll quickly uncover bottlenecks. Sensor tip: Deploy the SNMP CPU Load Sensor and Windows CPU Load Sensor for your CPU monitoring.

Hardware errors

Cause 3: Hardware errors

Devices or device parts can also break down or get a bug. The problem might lie in the RAM or a network card. As with overloads, these glitches can have a negative impact on your entire network.

Solution: With PRTG, you’ll keep a constant eye on your hardware. Errors in devices are often easy to detect, for the device’s readings will suddenly change. Sensor tip: System health sensors such as Buffalo TeraStation or NetApp and the SNMP Hardware Status Sensor.

Software errors in network devices

Cause 4: Software errors in network devices

Software errors are also quick to occur in network devices. And such glitches can lead to packet loss.

Solution: PRTG lets you spot software errors as soon as they arise. Example: by creating an Event Log sensor or using the PRTG API to create a custom sensor and thus individually read software logs and other messages.

Several tools in use, but no central overview

Cause 5: Several tools in use, but no central overview

Many administrators use several different tools. But these tools often have limited functions and are only used for specific things, such as tests. As a result, administrators find themselves without a constant, comprehensive monitoring solution..

Solution: With PRTG, you get one network monitoring tool that will monitor all your devices, traffic, and applications at all times, and that can be set to alert you in the case of problems as you see fit.

A sneak peek into packet loss measurement with PRTG


Your goal: 0% packet loss!

The goal of every administrator should be to attain 0% packet loss. By doing so, you’ll allow data packets to travel through your network in their entirety, error-free, and with the utmost in performance (read more about network performance).

Advantages of PRTG

Quick analysis

Upon installing PRTG, the Auto Discovery feature immediately gets to work. PRTG automatically searches for the devices in your network, and then creates appropriate sensors for them. The result: you’ll get a quick analysis simply by opening PRTG for the very first time!

Long-term analysis

Historical data lets you see how your network evolves in the long term. Example: with PRTG, you can identify and document a spike in traffic over a longer period of time.

Sensors included

All the above-mentioned sensors are included in the free trial version.Try the sensors risk-free, and decide for yourself if PRTG is the right tool for you.

Alarm feature included

PRTG comes with a customizable notification system. If a sensor sounds the alarm, you’ll automatically receive a notification. All the values of the alarm function can be personalized as you see fit.

Support included

PRTG also comes with quick and comprehensive support. Check out our knowledge base for numerous articles, videos, and instruction manuals. Our support team usually answers inquiries within 24 hours on business days.

Over 95% of our customers recommend PRTG


Paessler AG worldwide trialled PRTG in over 600 IT departments.
The aim was to tune the network monitoring software closer to the needs of the administrators.
The result of the survey: over 95% of the participants would recommend PRTG - or already had.

Recommend PRTG

Your network at a glance – even on the go

PRTG can be started within minutes and it's compatible with many mobile devices.


PRTG comes with all the features you need, plus more your IT infrastructure won't want to live without.


PRTG monitors these vendors and applications, and more, in one view!


Award winning solution

We work hard on making our software as powerful and easy-to-use
as possible for our customers each and every day.
Of course it makes us proud when we get awards for that.



Practical tip: “Hey Konstantin, what’s the best way to go about measuring packet loss?”

“The QoS (Quality of Service) Round Trip Sensor is perfect for measuring connection quality, which means it can also be used to measure packet loss between two points in your network. This sensor sends UDP packets from one end of a connection (usually a Windows computer with a PRTG probe) to another and then back again. You’ll therefore need two endpoints for QoS monitoring. To make this process as simple as possible, we’ve created the PRTG QoS Reflector Sensor. This sensor is basically a Python script which sends UDP packets from one endpoint back to PRTG. As a result, you won’t need to set up another Windows computer in your network to complete the round trip, which is usually the case with QoS sensors. The PRTG QoS Reflector is quick to implement and runs on all Linux-based systems, even a small Raspberry Pi which you can stick on the end of the connection to be measured

For more information and a download link on this open source tool, head on over to our knowledge base: QoS Round Trip Monitoring Without Remote Probes

Konstantin Wolff, Software Developer at Paessler AG

PRTG is worth it: You’ll optimize your entire IT!

The costs for a one-year PRTG license usually pay for themselves within a few weeks.

PRTG improves the reliability of your network

PRTG improves the reliability of your network

PRTG saves network management costs

PRTG saves network management costs

PRTG saves time spent on network management

PRTG saves time spent on network management

Traffic Monitoring: WMI, SNMP, Packet Sniffing,
NetFlow in comparison

How would you like to implement your bandwidth monitoring? PRTG features a variety of different options,
both with WMI, SNMP Monitoring, Packet Sniffing and NetFlow Monitoring.
Each of these tools has its own pluses and minuses. A summary: 





Packet Sniffer

xFlow (IPFIX, NetFlow, sFlow, jFlow)




Easy to complex (depending on filter rules used)

Can be complex (e.g., the switch must be configured)

Traffic can be filtered





Differentiate bandwidth usage by protocol or IPs





PRTG can show Toplists (Top Talker, Top Connections, Top Protocols, custom)





Filter bandwidth usage by IP





Filter bandwidth usage by MAC address





Filter bandwidth usage by physical network port





Monitor network parameters other than bandwidth usage





CPU load on the machine running PRTG



Higher, depends on the amount of traffic

Higher, depends on the amount of traffic

Excess bandwidth usage of monitoring



None (except when monitoring switch ports are used)

Depends on the traffic

PRTG simplifies your day

Our monitoring software works for you and promptly notifies you of potential issues.
It frees you to concentrate on your day-to-day tasks with peace of mind.


PRTG saves time

With PRTG, you get one central monitoring tool for your servers and entire network. Enjoy a quick overview of your whole infrastructure via our dashboard and app.

PRTG saves worry

Customizing PRTG is a breeze. Getting started or switching from another network monitoring tool is easy thanks to the PRTG auto-discovery and pre-configured device templates.

PRTG saves money

80% of our customers report substantial or even exceptional cost savings in the area of network monitoring. The experience shows that the costs for licenses have paid for themselves within a matter of weeks.


PRTG: The swiss army knife for sys admins

Adapt PRTG individually and dynamically to your needs relying on a strong API:

  • HTTP API: Access monitoring data and manipulate monitoring objects using HTTP requests
  • Custom Sensors: Create your own sensors for customized monitoring
  • Custom Notifications: Create your own notifications to send alarms to external systems
  • New REST API Sensor: Monitor almost everything that provides XML or JSON


Reader tips from our knowledge base


Made in Germany: The PRTG Network Monitoring Tool is the fruit of an engaged team. The company was founded by Dirk Paessler. The PAESSLER AG headquarters are located in the city of Nuremberg, in the heart of Germany. We combine typical German virtues such as high quality standards, industriousness, and commitment with international, cosmopolitan flair. Read more about our firm here. By the way: We are regularly looking for new recruits.

Case Studies: Airports, utility companies, banks, colleges, hospitals: PRTG is present in every industry. For each of our customers, business and organizational processes depend on the proper functioning of the network infrastructure. The PRTG customer satisfaction is close to 100%. Read in our case studies how our customers use PRTG.

Product tests: It goes without saying that we are convinced by the quality of PRTG. But what about the others? PRTG has always performed extremely well in tests. PRTG user “LanLine” sums it up best: “PRTG was already good several years ago, and has gotten better from version to version ever since.” Such has been our steadfast and sincere goal. Read more about monitoring software product tests and comparisons here.

Support: Our support team works hard every day to help customers solve their monitoring problems. Our goal is to resolve all inquiries within 24 hours (on business days). We've drafted a comprehensive manual and built up an extensive knowledge base featuring videos, webinars, and FAQs. All support, of course, is also included!

Getting started is easy: The trial version is free, which means you can try our monitoring tool risk-free. To switch to another version of PRTG, simply search for an appropriate license. You can upgrade any time you like.



Network Monitoring Software - Version (October 17th, 2018)


Download for Windows and hosted version available


English, German, Spanish, French, Portuguese, Dutch, Russian, Japanese, and Simplified Chinese


Up to 100 sensors for free (Price List)

Unified Monitoring

Network devices, bandwidth, servers, applications, virtual environments, remote systems, IoT, and more...

Supported Vendors & Applications

More >>

Related topics