Paessler AG’s award winning PRTG Network Monitor is a powerful, affordable and easy-to-use Unified Monitoring solution. It is a highly flexible and generic software for monitoring IT infrastructure, already in use at enterprises and organizations of all sizes and industries. Over 150,000 IT administrators in more than 170 countries rely on PRTG and gain peace of mind, confidence and convenience. Founded in 1997 and based in Nuremberg, Germany, Paessler AG remains a privately held company that is recognized as both a member of the Cisco Solution Partner Program and a VMware Technology Alliance Partner.

Share tech news, updates, or what's on your mind.

Sign up to Post

I am having trouble getting netflow to work on PRTG from Cisco 800, 1800 and 2800 series routers.  

I configure a router to export v5 or v9 flows - same problem on each.

I go into PRTG and set up a corresponding sensor.  

I want detail, so in the channels section I tick detail on a couple of categories.  set all the other bits like listening IPS and port number

The sensor will go to 'OK' with a green icon, but not receive any data.  I try their netflow test tool and can see data hitting the machine, so I know that netflow is set up and the firewall is not an issue.  Playing with settings yields no results.  

I then set up a netflow listener for another router, but I don't change the channel definitions and it works!

I realise I need more detail, so I go into the sensor settings and tick 'No' for a couple of channels and 'Detail' for the OTHER channel.  

The graphs disappear.  The sensor stays green, but it show no data.  I wait 1/2 an hour and still no luck

I set the channel definitions back to defaults and wait.  The sensor still does not show any data.  This would be consistent with the first router.  Channel definitions were changed from defaults and the sensor will never work.  

I delete the sensor and add a new one with the same settings as before.  No data shows.  A broken sensor persists even after deleting it.  

Is this a PRTG bug or am I doing something wrong?

I want detailed graphs so I can identify what data is hogging bandwidth, …
Hi all

I monitor my customers internet connections with PRTG and I am seeing spikes in outbound data.  It seems to be affecting about half of the connections I am monitoring.  It has been noticed because it saturates the upstream on some ADSL circuits providing VOIP, dropping calls.  

I have a customer with two networks, 1 voip and 1 data.  strangely, the bandwidth peaks affect both at the same time.  Then I noticed that it affects other customers at the same time!  I considered whether it is my monitoring platform, but some customers don't have them.    Attached are some graphs, with pink being the outbound data usage.  

The graphs show outages as a series of red dots, but I don't know if the line is down or whether it is simply that the upstream data is saturated so the usage data gets lost or the monitoring software times out before the SNMP response gets there.  

So for the purposes of this, please view the high upstream data and the outages as the same thing.  You will see that the times correlate across all the graphs, approx 9:05, 9~:30-9:45

Any suggestions as to what it is or even better - any ideas to prevent it would be greatly appreciated.  

The routers are all Cisco 867VAE, 887VA or 2821 and I use SNMP to monitor them.
I've been using PRTG successfully for network monitoring for years.
Now I'm investigating using it for WINDOWS UPDATES STATUS.
I think I've followed the instructions at:
But, it doesn't work.

This is on a peer-to-peer network.
The error says:
Connecting to remote server SB-BACKUP failed with the following error message : WinRM cannot process the request. The following error with errorcode 0x80090311 occurred while using Kerberos authentication: We can't sign you in with this credential because your domain isn't available. Make sure your device is connected to your organization's network and try again. If you previously signed in on this device with another credential, you can sign in with that credential. Possible causes are: -The user name or password specified are invalid. -Kerberos is used when no authentication method and no user name are specified. -Kerberos accepts domain user names, but not local user names. -The Service Principal Name (SPN) for the remote computer name and port does not exist. -The client and remote computers are in different domains and there is no trust between the two domains. After checking for the above issues, try the following: -Check the Event Viewer for events related to authentication. -Change the authentication method; add the destination computer to the WinRM TrustedHosts configuration setting or use HTTPS transport. Note that computers in the TrustedHosts list
I have configured all my switches to be on automatic device identification, and daily discovery.  The problem is, that when the scan runs, Everyday, it adds a lot of sensors to my existing switches that I don’t want added.  For example, I have attached a screenshot, showing how it adds every port that I already have added, and it also adds RMON ports as well. I can’t have it do that, as it takes tons of sensors, and I run out of sensors.  How do I configure PRTG to only add any new devices that were plugged into the switch since the last scan, not every port already added or any other RMON sensors?

Any ideas how to remedy this issue?
I have multiple Cisco switches, from 2960's to 3750's.  I have them all configured via SSH, and randomly, after a few weeks, I can't connect via SSH anymore into them.  I use PRTG to monitor them, and I noticed that when something happens to the certificate, that's when I can't log in anymore, so my monitoring system displays an error for the cert.  When configuring SSH, does the default cert expire after a certain amount of time or something?

Any ideas how to fix this?
Hi Experts,

I am looking for a network monitoring tool to deploy in our network.

I am doing some research and I have the following two options  (I have not tired them yet).

PRTG and NetCrunch.

Any recommendations on the above two network monitoring tools?  Have you used any of the two tools in your network and do you like what is offered ?


I'm trying to write a script that compares time between servers.
So, i'm getting time from one server and time from the second one.
With the help of new-timespan, i'm getting the difference in time, written in seconds.
After that I want to have a result:

If the difference is less or equal tha 15 seconds: No problem.
If the difference is bigger: Problem

The thing is: my script thinks the servers are always in sync, even if they are not.
So, I think my comparison is not working.

What am I doing wrong ?

I thought that, maybe it's because i'm comparing a variable to a number.
So I tried to convert the content of the variable to a string. Didn't help.
Placeing "" around the number of secaonds didn;t make a differnece as well.

The script:

# PRTG Exit codes
#	0	OK
#	2	System Error (e.g. a network/socket error)
#	3	Protocol Error (e.g. web server returns a 404)
#	4	Content Error (e.g. a web page does not contain a required word)

$server2 = "APP02"
$server3 = "APP03"

$time2 = Invoke-Command –ComputerName $server2 -ScriptBlock {Get-Date -format T}
$time3 = Invoke-Command –ComputerName $server3 -ScriptBlock {Get-Date -format T}

write-host $time2
write-host $time3

$diff = NEW-TIMESPAN –Start $time2 –End $time3
$sec = $diff.totalseconds
$sec -Replace "-","" | Out-String

if ($sec -le 15)
		$result = "0:OK - There is no difference in time"
elseif ($sec -gt 15)
		$result = "2:Error - Time is no longer in sync"

Open in new window

Hi Team, during checking for update for windows server 2008, the server seems to be slow. It is not just impacted only this server but the other servers on the same VMhost, as there were prtg alerts from several of the servers. Moreover VM Tool showing not up to date after checking for update. Please advise.
Is there a good free software for network monitoring?
Is there any windows application which is connect with Cisco router (SNMP) & monitor all connected network computers file transfer bandwidth utilization behind the router, Please suggest.
Hi People,

Can anyone please let me know what;s the example of the Read-only SNMP string for network appliance so that I can copy paste that into all of my Router, Switch, Printer and any other device that does not support WMI ?

When a file or folder is successfully connected to and either read or modified, can the various group and user permissioned that was used be found. So there might be several group memberships that gives the right and can all these be listed. In particular when something is denied, such as a network share or file can the actual point of denial be listed.
We currently are getting issues routing from out Managed ISP. They come back with link over utilization excuse for everything. So we want to setup a device or server that will monitor all traffic going to the router to provide reports. So we can measure and see where our problem areas are. We have no access to the router and can not enable snmp traps or any other managed protocols. So we will have to be the man in the middle sort of speak.

Any suggestions?
Is there a clean way to monitor a Microsoft Hyper-V Server 2012 R2 server for any hard drive failures?  I'm looking for a automated email solution but I will work with a manual process for now.  

To be clear, I'm looking to monitor the physical host that is on Microsoft Hyper-V Server 2012 R2 (Type I) that runs the guest OS behind it.    

Server is a Dell PowerEdge R410
We are looking for good network monitoring tools, to see what is going on in our network and were there are bottlenecks.

We have had a lot of complaints of end-users about slowness of our network, but we can find out where this is.

We are running on VMWare with hyper converged storage.

Any recommendations for us? Is doesn't have to be free.
I'm trying to setup a Cisco ASA with integrated Firepower module (NO Firesight server available) to send an e-mail whenever a threat condition is met.
According to the offical Cisco user guide (Link), it supports SNMP, syslog and mail. As far as I can tell from the GUI there is nowhere to configure the e-mail based alert.
The SMTP setup in general is complete and working.

Any ideas?

I have a Windows 2008 file server in site A and I plan to move it in site B. Users will stay in site A.

I need to know the network usage for the file server like that I can plan the bandwidth needs between Site A and Site B. How can I do that?
I have a client who is experiencing slow internet connection

ISP has told us it is to do with uploads being taken up bandwidth

anyone know a quick and easy way to detect which devices are using upload traffic

Router is TP LINK Archer D7

Thank you
What Internal Network Monitoring Software so you recommend to find where all INTERNAL Windows 2012 R2 server traffic is going on my 9+ year old CISCO switches ?
Hi all!

In our company we have decided to move forward and try different tools to monitor our IT infrastructure along with our business activity. We are looking for a holistic software able to allow us to monitor since the network and machines status (bandwidth, ram, hard disk, cpu, ...) to the state of our business processes. We have around 300 servers and we use different technologies such as Windows, AIX, Linux and HP-UX.
We run different applications, some are open source like MySQL, Apache and JBoss and other are enterprise solutions like Oracle, IBM Workflow, Message Broker, IBM Websphere, Tibco, ...
Apart from network, application and server monitoring we would like to monitor our public web sites, which are fully HTML developed in a proprietary architecture based on Java and public sited developed in Wordpress.

I have found some resources mentioning different network monitoring tools such as this article: Here there are many choices (best 16 network monitoring tools). However I am missing some solutions such as HP Openview, BMC or CA.

Said this, we would like to get from insight from some experts in the monitoring industry. After reviewing the best 16 network monitoring tools, I would like to know whether those solutions can scale and monitor above networks, servers and applications or should we move to HP Openview, BMC or CA.?

At this moment we have developed our own monitoring solution, which is …
I am looking for a simple network monitor for a small site. It just has a comcast cable modem that keeps going down. I Had Comcast out several times and replaced the modem. All I want to do is log the Up\Down status of the modem. I do not need real time alerts. I would like to be able to set it up on a old laptop for a few weeks just to collect information. There are only 3 PCs connected directly to this modem, so I don't need anything complex.
I have a Netgear WNR3500L that I manage somewhat with Netgear Genie. 'Somewhat' since my router is not really supported by the software. Is there an alternative?

One of the problems that I have is that I have connected an extra access point (DL2553) to the router, that does function, but remains unidentified in Genie.
HI every one we need Network monitoring tool for free ware
David Varnum recently wrote up his impressions of PRTG, based on a presentation by my colleague Christian at Tech Field Day at VMworld in Barcelona.

Thanks David, for your detailed and honest evaluation!

Author Comment

by:Kimberley from Paessler
Comment Utility
Hi Ryan,

Thanks for your message.  I'll flesh it out a bit and then submit it again.

I have a related question:  If I have a topic/article/post that I only want to post to the Paessler Topics page, does it still go through independent review?  I tagged "paessler" on several articles, but haven't been asked to review or approve them.  Who decides what can appear on our topics page?

(um, to avoid confusion, yes, I'd like to post this article to several topics, after it meets the requirements for an article.  My question is more a hypothetical one, in case I have things to post only to the Paessler topics page at some point).

Thanks for your help!

I have a broadband line with 10mb up and down capacity and it is maxing out.
I need to find out which user, or what process, is using the capacity.
Is there a GUI  based tool which you would recommend to help me achieve this?
Thank you






Paessler AG’s award winning PRTG Network Monitor is a powerful, affordable and easy-to-use Unified Monitoring solution. It is a highly flexible and generic software for monitoring IT infrastructure, already in use at enterprises and organizations of all sizes and industries. Over 150,000 IT administrators in more than 170 countries rely on PRTG and gain peace of mind, confidence and convenience. Founded in 1997 and based in Nuremberg, Germany, Paessler AG remains a privately held company that is recognized as both a member of the Cisco Solution Partner Program and a VMware Technology Alliance Partner.