Paessler Blog
Archive for Category "Network Monitoring Basics"
2011-Dec-13
How to Setup a Failure Tolerant Online Business in Six Steps—Step 5: Monitor Your Network
Once you've set up backup and recovery plans, make sure you know about the status of all of your systems: Your IT infrastructure including all crucial hardware components, your network connections, as well as your servers.
2011-Dec- 2
Beautiful Testing
If monitoring software is your business, there is one thing you cannot have enough of: Test systems running all over your network, under many different platforms, and on different hardware configurations.
2011-May-13
15 Website Performance Indicators You Should Monitor
Network Monitoring Tools such as PRTG allow you to constantly keep track of your websites. However, sometimes it can be daunting to know what to monitor.
2011-Apr-12
Hosting a Website Through Amazon CloudFront
In yesterday's post I mentioned that we are now hosting our corporate website through the Amazon Cloudfront content delivery network (CDN). Today I would like to share some observations we made while creating our new setup.
2011-Apr-12
Paessler Has a New Website—Now Fully CDN-Hosted
You may have already noticed our new look: Last week we launched our new website for www.paessler.com. This re-launch brought a new design to our homepage and we also migrated to a new hosting concept.
2010-Dec-22
PRTG Takes Part in Big RIPE Atlas Project
Creating a “weather map” showing the condition of the Internet all over the world is the declared goal of the Atlas project initiated by regional internet registry organization Réseaux IP Européens Network Coordination Centre (RIPE NCC). Located in the Netherlands, they aim to ship small hardware “probes” to all over the world. Volunteers on five continents are asked to plug in these small Ethernet devices into their personal or company’s network, building measuring points for “the last mile” of Internet access points in a large number of countries.
One of the subjects that should be investigated is the suitability of IPv6 in everyday use. As we all have to prepare for this, this project can be very important to all of us. According to Daniel Karrenberg from RIPE, these probes do not sniff any of the participants’ network traffic, but only perform measurements using Ping, DNS resolution via both IPv4 and IPv6, and trace route. RIPE already has longstanding experience in monitoring the traffic at Internet Service Providers, but the Atlas project will extend knowledge about the on and on growing Internet just into the homes. First—statistically unproven—monitoring results are already available.
2010-Mar- 1
Paessler Launches New Knowledge Base
Last week, Paessler's new Knowledge Base went online. There, you can find a compilation of resources about network monitoring in general and – of course – support and know-how information about PRTG Network Monitor and our other software products. As a mixture of Knowledge Base and forum, users cannot only receive information, but they can interactively ask questions and even share their knowledge by answering questions themselves. To become a contributor, you simply have to sign-up once and log in.2009-Dec-17
Howto: Exporting PRTG's Raw Monitoring Data Into Daily CSV or XML Files
With PRTG Network Monitor, you can analyze your sensor data in various ways. Exhaustive reports for your whole network can be generated as well as historic data reports for single sensors. Still, there are people who just need the data of a sensor in a convenient format to do their own statistics in external programs or to use Excel to do additional computations based on the monitoring data. That is why we have included a XML and CSV export function in PRTG. This function of the web interface is handy to export data every few days. But if you need daily data for one or more sensors an automatic solution is more comfortable. With the new CSVExport command line tool finally there is a way to export data of many PRTG sensors with one single line of script! You can use it as an on-demand tool or combine it with Windows task scheduler. Don't be confused by the name – CSVExport is capable of both XML and CSV data export!2009-Oct- 9
www.paessler.com Runs on New Hardware and Software
Today we have moved our website to new productions systems. We now have a "private cloud" made of two VMware ESX servers which run our five production servers as virtual machines - plus a load balancer and a firewall. The new setup looks like this:
2009-Jun- 3
Don't Use Windows Vista And Windows 2008 for Network Monitoring via WMI!
Many monitoring features of our PRTG Network Monitor software (as well as many other monitoring tools) are based on WMI. Everything is fine with WMI on Windows XP and Windows 2003, even for larger networks. But when Vista and Win2k8 come into the game it is a completely different story altogether. We have received reports from a number of users that ran into trouble when using WMI monitoring for larger networks - and all of them were using Vista or Windows 2008. We tried to find out what aspects affect the performance of WMI monitoring. We selected ten servers and PCs in our testing lab. All of them ran a different version of Windows. We measured the WMI performance between them.2009-May-26
Introducing Paessler Multi Server Simulator
For testing purposes Multi Server Simulator simulates a virtual network of HTTP, FTP, SMTP, or DNS servers plus any number of SNMP-based switches - all on a standard Windows PC. It is an indispensable tool for the evaluation and testing of network management and network testing tools.2009-Feb-13
Monitoring the Available Bandwidth (Part 2)
Back in August I have already posted an article which explains how complicated it is to measure the bandwidth that is actually available for you. One of the problems I mentioned was that if you want to exactly measure the available bandwidth you would have to saturate your data line and then measure the achieved bandwidth. But if you saturate your data line you are actually prohibiting all other traffic. Not a good idea for everyday life.2008-Dec-18
"Cannot Assign Requested Address (#10049)" Errors in Webserver Stress Tool under Vista
Recently some users of our product Webserver Stress Tool found out that they could not perform any load tests anymore - but it had worked fine on their Vista computers before.2008-Oct-16
Monitoring your Internet Bandwidth Usage with a LinkSys RVS 4000 Router and PRTG Network Monitor
Many users of the freeware of PRTG Network Monitor use the software to simply monitor their Internet router and to find out how much bandwidth they consume in a month. The Linksys RVS 4000 is a good and common example and we will look at its details for this blog post. Many other Internet access routers will show quite similar behaviour. If you let PRTG's auto-discovery scan the router's IP you will get the following sensors:2008-Aug-20
How can I monitor my available bandwidth 24/7?
We receive questions like this every few days. User of our monitoring products want to know if their ISP or hosting service is actually providing them with the available bandwidth that they are paying for. But measuring the actually available bandwidth is almost impossible. Let me explain this:2008-Jan- 8
Installation of PRTG Traffic Grapher on Ubuntu Linux
You do not need a Windows based computer (and a Windows license) to use most of PRTG's features. You can also run PRTG Traffic Grapher 6.x on Linux. Using the "Wine Library" (which emulates Windows system calls) you can run PRTG like most other Windows apps on Linux systems. Of course some hardware/driver-based features like Packet Sniffing do not work. For this tutorial the following steps will- create a virtual machine in VMWare Workstation 6,
- install Ubuntu 7.10 onto the virtual machine,
- install Wine 0.9.52 onto Ubuntu and
- install PRTG 6.x onto Ubuntu/Wine
2007-Nov-14
Downtime of paessler.com website due to a traffic accident
Apparently a traffic accident is to blame for almost 3 hours of downtime for our corporate websites in the night from Monday to Tuesday. A truck driver lost control over his vehicle due to low blood sugar and drove into a power transformer on the side of the Dallas-area data center of Rackspace Inc. in Grapevine, Texas, which hosts our server park.2007-Oct-19
Handy SNMP resources on the Cisco website: Cisco MIB Listings, MIB Locator, and OID Translator
Recently we came across the following three pretty notable pages provided by Cisco, allowing users to find Cisco MIBs and to discern OID segment almost at a glance.2007-Oct-17
Bug in Cisco ASA 5505 causes PRTG to report the same traffic on all VLANs
We have had multiple queries regarding strange, respectively wrong readouts when monitoring certain ASA equipment. As we found out today, the problem is a bug in the 7.2 OS causing the SNMP iftable to forward erroneous return values to monitoring software, such as PRTG. Instead of graphing PER vlan values, this bug results in graphing the total number of untagged vlan packets for each vlan.2007-Sep-12
Most common causes of network outage include inadequate bandwidth, excessive file streaming and device misconfiguration
Our latest press release reports about the latest survey results from users of PRTG Traffic Grapher. It reveals that bandwidth management software is a key component in preventing network downtime.2007-Aug-29
Negative PING times on AMD Dual Core Processors - Solved
[UPDATE Oct 2010] There seems to be an easier solution than the one mentioned below: By using the "/usepmtimer" boot.ini flag (simply add this line to boot.ini) you can change the time source for QueryPerformanceCounter from TSC to the PM timer which is a global time source. Note: This information was taken from here and http://wiki.ljackson.us/Negative_Ping_Time#BOOT.ini_Solution, but we did not test it ourselves on AMD CPUs). -------------- In recent weeks we have received reports about negative PING time measurements (e.g. -5 ms) from users of our monitoring products. "Great", we thought, "our software has overcome the laws the physics and is able to received network packets before they are actually sent". But now there are more and more hints showing up around the Internet that we will not receive the Nobel price in physics...2007-Jul-17
Survey Finds PRTG Traffic Grapher Saves Network Administrators Hours a Week in Network Monitoring Time
2007-Jul- 9
Detecting Common Network Problems, Part VII: Intrusions
Intrusions to your network can easily occur at anytime and often come from unexpected sources. Intrusions from hackers, internet worms, viruses, Trojans, or just people curious about what you happen to have on your network pose great threat to the security of you network. Network Monitoring allows you to identify network weaknesses, as well as detect intrusions should they occur.2007-Jul- 5
SNMP on Windows Vista rendered dysfunctional by NOD32 Anti Virus
Since Vista came out we had a strange problem with our Vista workstations: We were absolutely not able to query them through SNMP (using our PRTG or IPCheck as well as any other SNMP tool). SNMP requests simply timed out and were not returned by these Vista machine, regardless of the version (Vista Business or Ultimate). The SNMP service was properly installed and working, netstat reported nothing unusual.2007-Jul- 5
Detecting Common Network Problems, Part VI: Software Problems
Software-related network problems can cause one or more computers or devices to lose the ability to communicate with other devices on or outside the network.2007-Jul- 2
Detecting Common Network Problems, Part V: Network Collisions
Although the word sounds negative, collisions are a normal part of a healthy network. A collision is the mechanism used by the network to control access and to allocate shared bandwidth among devices that want to transmit at the same time on a shared medium. Collision detection allows the two devices to identify that they both want to transmit at the same time. While collisions are normal, a high collision rate can indicate network problems.2007-Jun-28
Detecting Common Network Problems, Part IV: Connectivity Problems
Connectivity problems occur when devices on the network cannot communicate with other areas of the network due to hardware or software problems. With Network Monitoring, you can detect a connectivity problem before users or customers even notice it.2007-Jun-25
Detecting Common Network Problems, Part III: Hardware Problems
Hardware problems occur when a network device is not working properly and cannot send or receive some or all data. With the myriad of hardware devices connected to the network at any given time (including routers, firewalls, servers, switches, etc.), detecting when a specific device malfunctions is vital.2007-Jun-21
Detecting Common Network Problems, Part II: Cable Problems
Cables are a vital part of any network. Cables are also prone to wear and tear, which can cause problems across the network. The obvious solution would be to make sure you install cables in places that do not get a lot of foot traffic, or places hidden from curious hands. The fact is, somewhere on the network, there are probably at least a few cables exposed to possible damage.2007-Jun-18
Detecting Common Network Problems
Network Monitoring allows you to accurately recognize and diagnose networking problems with the goal of keeping your network running optimally. Your network is a vital business asset, and maintaining maximum uptime and availability is the highest priority. To keep your business operations and processes running smoothly, 24x7x365 monitoring and notification are required to detect the various problems, failures, and performance issues before they have a chance to affect your employees or customers.2007-Jun- 4
Preparing for the Moment of Disaster
Monitoring, knowing what to monitor, and knowing whom to tell, still do not provide the whole solution for proper Network Monitoring; you must also know what to do when monitoring discovers problems.2007-May-31
OK, you are monitoring your network. Now: Whom To Tell The Results
Once you perform regular monitoring, it will not help if you keep all the results and findings to yourself. Knowing whom to tell what information, and when to tell it, is a major necessity.2007-May-29
The three most important readings that you should monitor
Merely implementing a Network Monitoring solution is not enough. You should also know which aspects of your network need monitoring.2006-Nov- 1
Five reasons to get serious about bandwidth monitoring
Here is a short list of the top five reasons why you seriously should consider to implement bandwidth monitoring in your network:2006-Oct-31
The 64 Bit Counter Mystery: Trouble with a HP Procurve Gigabit Switch
We had upgraded the last remaining dark and slow 100 Mbit corner of our data center from 100 Mbit Ethernet to Gigabit Ethernet the other day. We installed an HP Procurve 1800-8G which offers Gigabit for 8 ports. As usual we began to monitor this switch using our PRTG software and found quite a surprise: PRTG reported steady peaks of 2.000.000 gigabit/s (2.000 terabit/s). Obviously something went wrong here.2006-Oct-30
How to Choose the Right Bandwidth-Monitoring Solution
If you work in the networking industry, you no doubt spend more time than you'd like putting out the proverbial fire and then wondering how it started. Your network -- however well-conceived or well-engineered -- will, invariably, create problems for you and your team at some point. So for those of us in the business of preventing problems, it's essential that we lean on our bandwidth-monitoring solution and put it to work for us.2006-Oct-26
Using PRTG and IPCheck with Windows Defender
We have been informed a couple of times that Microsoft's anti-spyware software Windows Defender seems to be having issues with our software. After various tests, we are pretty certain this is not the case - if Defender is properly configured. We had Defender and our own PRTG Traffic Grapher and IPCheck Server Monitoring up and running on various test installations for a couple of days and were unable to discern any particular issues.2006-Sep-21
Top 5 reasons for sudden traffic peaks shown by bandwidth monitoring
Sometimes users of our network monitoring software PRTG Traffic Grapher contact our support team and report peaks in their bandwidth monitoring graphs. Most of these peaks only look like unusual high traffic, but some users have even seen spikes like 10 GBit/s for a sensor that actually monitors a 2 MBit/s connection.... Well, a gigabit peak for a data line with megabit rating clearly has to be regarded as a technical problem. But in most other cases our support team together with the customer have found out - after some investigation - that the reported peaks were correct. There were caused by a number of different reaons and here is our Top 5 list of these resons:2006-Sep-19
Changing the colors of the sensorlist of PRTG Traffic Grapher
With version 6 we introduced a less colorful look&feel for the sensor list of the web interface and Windows GUI. First let me shortly explain why we did what we did: We sat together with graphical designers and users of PRTG and looked at the whole interface. Apart from other things we found that it was too colorful: too many colors seemed to distract from the important information. The new look is intended to- to make the list easier legible and
- make it possible to emphasize and de-emphasize important and less important areas of the interface.
2006-Sep-18
Free ebook from Cisco Press: "Cisco Router Configuration"
Cisco press offers a free ebook download on their website for the book "Cisco Router Configuration, Second Edition". Even though the book is from 2001 it offers a wealth of well written information about the basics of networking, Cisco device configuration, TCP-IP configuration. It even covers IPX and Appletalk.
2006-Sep-11
The Monitoring Triplets: Availability, Speed, and Usage
Merely implementing a Network Monitoring solution for your network is not enough. The biggest part of the work begins right after choosing and installing a monitoring solution. Now it is time to select which aspects of your network you are going to monitor.2006-Aug-31
Searching for problems on a slow Unix/Linux server
There is a nice article on IBM's developer works website that explains how to use various command line tools to analyze runtime problems on Unix systems:When your UNIX® system runs slow, it is vital that you discover what the problem is as quickly as possible so you can get your system back into the normal operating mode. There are many causes for a slow system, but actually identifying the problem can be exceedingly difficult. In this article, study examples of how to identify and diagnose the cause of your slow running UNIX system to get your machine running properly again.
2006-Aug-21
Top Five Reasons to use Network Monitoring in Your Network
If your company conducts business via the World Wide Web, optimum performance of your business website is not only critical for the growth of your business but also for its survival. Listed below are the five most important reasons why you should always monitor your website, and its other components.2006-Aug-17
Analyzing a Slow Exchange 2003 Server
You have been there: All servers seem to be getting slower over time. Always. But is it really the problem? Does it really hurt your business? And what can you do against it? For Windows servers there are multiple reasons for a slowdown over time:- fragmented disks
- overflowing TEMP folders
- processes that eat more and more RAM
- too many processes on a system or cpu-intensive processes
- hardware problems
- faulty software
2006-Aug-16
Monitoring System Parameters like Memory, CPU and Disks on Linux Systems via SNMP
Every other day users of our monitoring products PRTG Traffic Grapher and IPCheck Server Monitor ask us how they can monitor system parameters like CPU load, memory load, swap file size or disk usage on Linux and Unix systems. Today we have published a new step-by-step article in our knowledgebase that explains how to set up system parameter monitoring for Linux systems. This screenshot shows part of the list of available sensors for a Linux system (using IPCheck Server Monitor):
2006-Aug-15
Why Network Monitoring Is Important For Any Business
Before we begin to talk about the importance of Network Monitoring, let's see what "Network Monitoring" exactly is. The free online encyclopedia Wikipedia says:"The term Network Monitoring describes the use of a system that constantly monitors a computer network for slow or failing systems and that notifies the network administrator in case of outages via email, pager or other alarms."I would extend this definition by not only monitoring the network for outages but also monitoring the performance and usage of a network.
2006-Aug- 9
Interview: The Benefits of Network Monitoring (Part 2)
This is of part 2 a transcript of an interview between me and a journalist who wanted to know more about the benefits of network monitoring. We were talking about the benefits of an uptime/downtime monitoring solution like IPCheck Server Monitor as well as the benefits of bandwidth and usage monitoring products like PRTG Traffic Grapher (see Monday's post for the 1st part): The benefits we talk about in this part are:- 4. Benefit: Secures your turnover, because you will know about problems literally within one minute and you can take immediate action
- 5. Benefit: Gives you a chance to switch to your redundancy systems.
- 6. Benefit: Know about performance bottlenecks before your customers find out?
- 7. Benefit: Long term performance data gives you a chance to plan and implement upgrades (e.g. new server hardware, leased lines) without the need for hectic solutions
- 8. Benefit: Control whether your provider meets your service level agreement.
2006-Aug- 8
Installing the NET-SNMP daemon on Debian Linux
In order to monitor system parameters like memory and CPU load on Linux systems we recommend to install an SNMP daemon on the system. Then you can monitor the parameters using SNMP. Today I found a tutorial on the debianhelp website that explains in detail how you can install the NET-SNMP service on a Debian Linux system. As soon as this service is installed and configured you can monitor system information like CPU load on a Linux system using PRTG Traffic Grapher and IPCheck Server Monitor.2006-Aug- 7
Interview: The Benefits of Network Monitoring (Part 1)
This is a transcript of an interview between me and a journalist who wanted to know more about the benefits of network monitoring. We were talking about the benefits of an uptime/downtime monitoring solution like IPCheck Server Monitor as well as the benefits of bandwidth and usage monitoring products like PRTG Traffic Grapher: The benefits we talk about in this part are:- 1. Benefit: Increased profits: Avoid losses caused by undetected system failures
- 2. Benefit: Peace of mind: As long as you do not hear from IPCheck via email, sms, pager, etc. you know everything is running fine, and you have more time to take care of other important business
- 3. Benefit: Ease of use: IPCheck Server Monitor is easy to set up and easy to use.