CEO's Blog
Archive for the 'Network Monitoring Basics' Category
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Monday, March 01 2010
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.
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Friday, February 05 2010
Video Tutorials From Paessler Support Team Available!
Members of our support team have created two nice video tutorials to make it even easier for you to start monitoring your network with PRTG Network Monitor.
Lean back a few minutes and learn how to install our software and let PRTG do all the work by using the built-in auto-discovery function which searches for and adds on your network devices automatically. Another tutorial shows how you can set up different notifications in PRTG to keep you informed whenever there's something special going on in your network – be notified via email, ICQ, SMS text message and more.
Check out the videos at our support website.
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Thursday, December 17 2009
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!
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Friday, October 09 2009
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:
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Wednesday, June 03 2009
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.
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Tuesday, May 26 2009
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.
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Friday, February 13 2009
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.
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Tuesday, December 30 2008
WMI Tester Tool updated
Today we have published updated version 2 of our WMI Tester Tool.
Since the release of PRTG Network Monitor 7, which can make massive use of WMI for monitoring in larger networks, we have seen quite a few customers having trouble with their WMI setups. These problems were caused by misconfigured firewalls, incorrect domain accounts, bad DCOM settings and many more. WMI Tester can be of a great help in such a situation - especially combined with our knowledgebase article "Paessler's Guide to Troubleshooting WMI Problems".
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Wednesday, December 24 2008
Merry Christmas And a Happy New Year!
Thank You For Relying in Our Products
We deliver high quality network monitoring and web server stress testing software that helps our customers keep their network up and running.
But we could not do this without your support: purchasing our products, helping us to improve our software with your feedback, and recommending us to your friends and colleagues enables us to continuously improve our tools. Thank you.
We wish you happy holidays and a lucky and successful year 2009.
PS: The photos were taken on Germany's most famous Christmas Market "Christkindlesmarkt" in our hometown of Nuremberg, Germany, just a 5 minutes walk from our offices.
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Thursday, December 18 2008
"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.
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Monday, November 17 2008
Paessler's Guide to Troubleshooting WMI Problems
Every so often customers using our monitoring tools (e.g. PRTG Network Monitor) report issues when trying to monitor their systems using WMI (Windows Management Instrumentation) sensors. In most cases, these issues stem from a malfunctioning WMI configurations/installations.
Today we have published our Guide to Troubleshooting WMI Problems that will help users of PRTG to track down most issues.
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Thursday, November 13 2008
SNMP Tester Debug Tool Updated
Today we have uploaded a new version of SNMP Tester, our simple but efficient testing tool for SNMP connections. With SNMP Tester you can run simple SNMP requests against a device in your network.
The program is based on the SNMP technologies that are also built into PRTG Network Monitor and the idea is to have a tool that enables the user to debug SNMP activities in order to find communication and/or data problems in SNMP monitoring configurations. If the SNMP connection works with this test program it will also work with PRTG.
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Wednesday, November 12 2008
Creating Artificial NetFlow Data Streams for Testing Purposes Made Simple
Our latest freeware tool Netflow Generator creates artificial NetFlow Version 5 data streams without the need for NetFlow compatible hardware. It is the perfect tool to test the NetFlow functionality of PRTG or other NetFlow compatible programs.
NetFlow Generator runs on a PC and sends NetFlow 5 Packets (via UDP) to a specific target computer which processes the data. You can create various patterns and loads of traffic. While the simulator is active it will create NetFlow packets which contain information about the selected traffic pattern. These packets contain the same information as a router/switch would send if it saw the simulated traffic pattern (the simulated traffic itself is not generated).
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Wednesday, November 12 2008
MIB Importer Tool Updated
Today we have released a new version of our MIB Importer Tool. The MIB Importer is used to convert so-called "SNMP MIB files" into a format suitable for our monitoring applications, especially PRTG Network Monitor. MIB files are usually supplied by device vendors and describe the available monitoring objects of a device.
This new version 2.0 includes support for PRTG Network Monitor 7 and includes many improvements of the MIB parser aimed at improving compatibility with MIB files that only conform loosely to the RFCs (which happens quite often actually).
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Tuesday, November 11 2008
Netflow Tester Debug Tool Updated
Paessler NetFlow Tester is a small program that simply dumps the data of all NetFlow packets that a computer receives from a Cisco router. This can be useful when debugging bandwidth monitoring configurations based on Cisco's NetFlow protocol, e.g. in order to find out whether packets actually reach the target system.
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Thursday, October 16 2008
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:
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Wednesday, August 20 2008
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:
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Wednesday, July 30 2008
Whitepaper: The Role of Network Visibility in IT Operational Risk Management
The whitepaper illuminates the importance of network management to many areas of IT operational risk management. Certainly its role in managing potential network problems such as switch failures and overloads is a major reason for investing in network management software.
However, it also can have a role in identifying other potential problems including the download of inappropriate material on business networks and prioritizing various classes of network traffic for optimal business performance. In a world in which even sub-second delays in transactional traffic can cost, these can be crucial elements to address. -
Tuesday, June 17 2008
New Article: Network Visibility: The Key to Risk Management
Today a new article of mine was published by the Enterprise Systems Website www.esj.com:
IT faces three major classes of exposures:
- Technology risks
- Legal and personnel risks
- Natural and man-made disasters
Read more here:
Network Visibility: The Key to Risk Management: These three steps can help you establish a "reality-based" risk mitigation plan -
Tuesday, March 25 2008
Article: "Put monitoring strategy on offensive"
Understanding bandwidth and resource consumption is the key to better network performance management - this the main point in my recent article "Put monitoring strategy on offensive" for CommunicationNews magazine.
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Monday, January 21 2008
Why we do not recommend installing software via Remote Desktop
In order to avoid installation and configuration issues, it is generally better to install PRTG and IPCheck directly on the host server, seeing as certain system pop-ups are not properly carried forward when connecting to the server via a RDP session.
Read more in our Knowledge Base Article.
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Tuesday, January 08 2008
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
- create a virtual machine in VMWare Workstation 6,
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Tuesday, December 18 2007
Paessler gets its website hosting from beyond content
Our websites are programmed and hosted by our service company beyond content. Here is what they say about themselves:
"Als Fullservice Internetagentur bietet beyond content seinen Kunden umfassende Unterstützung aus einer Hand für alle Online-Ambitionen. Mit langjähriger Erfahrung bei Beratung, Konzeption, Screendesign und Programmierung entwickelt beyond content Datenbank- und Multimedia-Applikationen, Redaktionssysteme und Templates, Shops und Konfiguratoren für individuelle Online-Projekte. Die Kunden erreichen ihre Ziele mit benutzerfreundlichen und informativen Internetseiten, auf denen sich die Besucher intuitiv zurechtfinden!"We can only recommend their services!
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Monday, December 10 2007
Monitoring Macintosh Computers under Leopard using SNMP
As of the new Apple operating system Leopard, Macintosh users are able to monitor their resources and their hardware based on SNMP. John Welch has posted an article explaining the implementation and functionality of this newly included SNMP system at The Unofficial Apple Weblog. You can find the article under http://www.tuaw.com/2007/12/05/john-welchs-guide-to-snmp-on-leopard. SNMP is one of the ways to monitor your systems with both our flagship software products, PRTG and IPCheck.
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Wednesday, December 05 2007
Data Execution Prevention (DEP) may cause SNMP Helper or PRTG's packet sniffer to fail
Some customers have had issues with installations of SNMP Helper Pro when the Data Execution Prevention (DEP) feature of Windows 2003 server was enabled. Also in some situations the packet sniffer feature of PRTG has shown problems with DEP enabled.
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Sunday, December 02 2007
How to Discern Excessive Bandwidth Usage using PRTG Traffic Grapher
PRTG allows administrators to discern actual bandwidth usage in their network based on multiple parameters, such as IP addresses, port numbers, protocols, etc., using either packet sniffing or NetFlow collector sensors. A new article in our knowledgebase explains how this feature can be used to find out who (or what PC/Server) is causing traffic peaks and excessive bandwidth usage in a network.
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Wednesday, November 14 2007
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.
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Friday, October 19 2007
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.
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Wednesday, October 17 2007
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.
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Wednesday, October 10 2007
New diagnostic tool: Paessler WMI Tester
WMI ("Windows Management Instrumentation") is Windows built-in monitoring and management technology (introduced with Windows 2000). It's a great way to monitor Windows systems in your network.
IPCheck Server Monitor already works with WMI. As accessing WMI counters over a network is not exactly trivial, our new Paessler WMI Tester is a tool that can be used to test the accessibility of WMI counters in a quick and easy manner.
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Wednesday, September 12 2007
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.
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Friday, September 07 2007
External WMI access on Windows Vista rendered dysfunctional by NOD32 Anti Virus
The other day we found a Vista machine in our network that we could not remotely monitor from the LAN using WMI. But WMI monitoring was working fine on all our other Vista machines...
Finally we discovered that on the specific machine the NOD32 anti virus software was causing the same problems for WMI as we had already seen for SNMP (see my post from July 5th about dysfunctional SNMP on Vista).
As soon as we applied the procedure described in the article from July everything was fine for WMI.
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Wednesday, August 29 2007
Negative PING times on AMD Dual Core Processors - Solved
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...
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Tuesday, August 21 2007
Network Monitoring provides Transparency and Insight into the IT Infrastructure
A properly working systems environment is indispensable for all enterprises. System outages - web shops, applications, or employees' PCs for example - can have a hugely negative impact on business processes and working climate. And it is the IT department that becomes the focus of attention, getting all the criticism, yet its achievements are often not appreciated, because the staff don't understand what they do.
Read more in our latest press release.
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Monday, July 23 2007
Does my Cisco device (Router/Switch) support NetFlow Export?
It can become quite complicated to determine which Cisco devices support NetFlow Export and in what version. PRTG Traffic Grapher currently only supports NetFlow V5.
We have compiled the information about this topic which is available to us in a new article in our knowledge base.
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Tuesday, July 17 2007
Survey Finds PRTG Traffic Grapher Saves Network Administrators Hours a Week in Network Monitoring Time
In our latest customer survey we found that most users report half an hour of time savings per week or more after installation of PRTG Traffic Grapher.
We had 560 customers answering the survey and they told us,
- that over 70 percent report that network uptime/downtime monitoring and alerting are among the most important network management tasks for their organization
- that over 67 percent report that bandwidth usage and traffic monitoring are among the most important
- that 45 percent saw savings in network management time and
- that over 95 percent (!) would recommend the product to a colleague or peer
Read more in our press release.
- that over 70 percent report that network uptime/downtime monitoring and alerting are among the most important network management tasks for their organization
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Monday, July 09 2007
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.
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Thursday, July 05 2007
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.
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Thursday, July 05 2007
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.
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Monday, July 02 2007
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.
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Thursday, June 28 2007
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.
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Monday, June 25 2007
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.
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Thursday, June 21 2007
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.
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Monday, June 18 2007
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.
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Monday, June 04 2007
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.
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Thursday, May 31 2007
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.
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Tuesday, May 29 2007
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.
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Thursday, May 24 2007
MIB Importer converts proprietary device MIB-SNMP files to enable management by Paessler's Network Monitoring Applications
Today Paessler officially announced MIB Importer, a free software tool for existing Paessler customers that seamlessly converts proprietary network device Management Information Base (MIB) data into a format that is compatible with Paessler's PRTG Traffic Grapher and IPCheck Server Monitor applications. This enables administrators to quickly and easily configure SNMP sensors for gathering critical network diagnostic information. By providing a hassle-free solution to monitoring, Paessler allows network administrators more time to focus on strategic initiatives.
Read more in our press release.
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Tuesday, May 08 2007
Webserver Stress Tool ensures websites' optimal performance
The way a web site runs is often critical to the operation of a business, so it is vitally important that any problems that might affect a site's optimal performance levels are identified - before they happen.
Paessler's Webserver Stress Tool has been designed for exactly this purpose. It is a comprehensive HTTP-client/server test application that will simulate hundreds, or even thousands, of simultaneous and independent users.
Read more in our latest press release.
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Monday, November 13 2006
Five Questions to Ask Yourself as You Consider Monitoring Solutions: Part 5/5
Question #5: Does It Support the Three Common Methods for Acquiring Network-Usage Data?
A comprehensive bandwidth-monitoring solution should support Packet Sniffer applications, as well as SNMP and NetFlow protocols. Each data-acquisition method has pros and cons -- depending on your network configuration and your monitoring needs. That said, your bandwidth-monitoring solution should support all three methods and allow you to effectively monitor your traffic regardless of your current or future network configuration.
Here is a brief description and analysis of each method:
- Packet Sniffer: The Packet Sniffer inspects all network data packets passing a PC's network card(s) and classifies network traffic by IP address, protocol and other parameters.
Advantage: Exact data, traffic can be accounted by IP and protocol.
Disadvantage: High load on monitoring system for high-traffic systems; network topology must be changed, so that all packets in the network are sent to the analyzing machine.
- NetFlow: The NetFlow protocol is supported by most Cisco routers to measure bandwidth usage. Although it is the most complex method to set up, it is also the most powerful method for monitoring high-traffic networks and can classify traffic by IP address, protocol and other parameters.
Advantage: Best choice for high-traffic networks that need protocol analysis
Disadvantage: Only works with Cisco routers.
- SNMP: Simple Network Management Protocol is the most basic method of gathering bandwidth and network-usage data. It can be used to monitor bandwidth usage of routers and switches -- port-by-port -- as well as to perform device readings for memory and CPU load.
Advantage: Low bandwidth and CPU load caused by monitoring itself. Best choice for high-traffic networks that don't need protocol analysis
Disadvantage: Traffic can only be monitored in totals per device/port and cannot be differentiated by protocol.
Note: Only Packet Sniffer- and NetFlow-based monitoring methods allow you to measure traffic by IP address, MAC address and/or protocol. SNMP-based measurements are strictly port-based. - Packet Sniffer: The Packet Sniffer inspects all network data packets passing a PC's network card(s) and classifies network traffic by IP address, protocol and other parameters.
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Friday, November 10 2006
Five Questions to Ask Yourself as You Consider Monitoring Solutions: Part 4/5
Question #4: Is the Price Right?
Cost, of course, is a major part of any procurement, but it should never be the sole or even leading variable in your evaluation of a monitoring solution. Bandwidth monitoring is simply too important to the overall success and viability of your operation for your team to be blinded -- one way or the other -- by price. Occasionally, cost can give you insight into how effective a solution may be, but it's certainly not a fail-proof predictor of efficacy.
Frankly speaking, it's both impractical and imprudent for your team to purchase solutions based almost entirely on price. As one can imagine, networking vendors weigh a complicated and unique set of internal and external variables to arrive at their various price points. In other words, price isn't necessarily linked to a product's functionality or features. And, as with any purchase, you should not use cost as a justification to bypass the due-diligence or research process that precedes any major procurement.
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Wednesday, November 08 2006
Five Questions to Ask Yourself as You Consider Monitoring Solutions: Part 3/5
Question #3: Does It Have an Intuitive Interface That Can be Customized?
It's critical that your solution allows users to create customized dashboards with graphs and tables that meet their specific departmental or project-based needs. Without customization, your monitoring tool may initially be well-received by team members, but, over time, it will likely become an under-used resource and be seen as something of a generic and predictable tool with limited practical functionality. Without customization, monitoring solutions become part of the operational status quo and, quite naturally, less of a staff priority. By comparison, customizable solutions prompt managers and team members to be engaged in the process, focus their monitoring efforts and take action to improve overall efficiencies. Monitoring bandwidth shouldn't become a static procedure, but, rather, an interactive one that complements constantly changing operational goals.
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Monday, November 06 2006
Five Questions to Ask Yourself as You Consider Monitoring Solutions: Part 2/5
Question #2: Does It Offer Secure Remote Access?
Ideally, the GUI of your preferred monitoring solution will be Web-based. In a truly global economy and in an era of increased telecommuting and flex schedules, your monitoring solution should be available to your entire team at any time -- no matter where they perform their work on any given day. Finding a Web-based solution becomes essential if your team isn't centralized in one office and is, instead, comprised of members in various far-flung offices. The more your staff can access the monitoring solution, the more they'lll use it and the more they'll pre-empt problems linked to performance and availability. Simply put, your monitoring solution shouldn't be anchored at a single location and hamstrung by basic geographic or logistical constraints when various Web-based applications exist.
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Wednesday, November 01 2006
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:
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Tuesday, October 31 2006
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.
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Monday, October 30 2006
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.
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Thursday, October 26 2006
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.
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Thursday, September 21 2006
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:
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Tuesday, September 19 2006
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.
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Monday, September 18 2006
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. -
Monday, September 11 2006
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.
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Thursday, August 31 2006
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.
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Monday, August 28 2006
Long-Term Intrusion Detection using Network Monitoring
Network Monitoring can alert you about security breaches and intrusions by detecting sudden changes in usage pattern and traffic behavior. For example, many worms or viruses cause sudden changes in the amount and type of network traffic when they start to spread.
Modern computer hackers pose a strong threat from the outside. If an organizationâ??s network is unprotected, a single hacker can easily wreak havoc to vital resources. Just as monitoring and security applications have evolved, hackers have gladly stepped up to the challenge.
You may think that having good defensive features like VPNs, firewalls etc. is enough. But hackers are always using new and more sophisticated methods to try to access company systems. Tools like automated hacker robot (or â??botâ?) and Trojans perform automated sweeps of the Internet searching for devices with access vulnerabilities. As soon as they find one they try to break in and use your systems for malicious activity. Most of that activity will lead to changes in network usage pattern and to downtimes in your own services.
Also keep in mind that the most dangerous threats come from the inside: employees that install or run malicious software â?? either by intention or because they do not know better â?? pose a much larger threat to your network. If that happens you have the problem inside of your network.
The conclusion is that you have to prepare for these threats in two ways: Use pro-active tools like firewalls and intrusion detection systems (IDS) as well as proper monitoring of your network usage. For a new threat your IDS and firewall may not be prepared yet. So only with monitoring you will be able to see intrusions that your firewall or IDS device may not yet be aware of.
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Wednesday, August 23 2006
Ensuring Your Business' Success with Network Monitoring
Computers and computer networks are increasingly becoming indispensable for business. In fact, fully web-based businesses rely completely on computers, as almost every aspect of their business relies on their online presence.
This means that even a little problem with the network or the server can seriously affect the business.
The most important keyword here is "availability". Availability is measured in percent. This percentage is calculated by dividing uptime (the time a system was available) by the time this uptime was measured (per hour, day, or month).
"10 percent downtime" may not sound horrible at first glance, but 10 percent of one year equals 36.5 days. That is more than a month of lost sales! This can actually cause an economic loss of far more than 10 percent of your total sales. Customers who repeatedly experience a non-functional website will immediately turn away to your competitors and never return.
For most companies, an availability of 99.9 percent (less than 90 seconds of downtime per day) can be reached with reasonable effort and without paying a fortune. In fact, many ISPs offer 99.9 percent SLAs to their hosting costumers.
Today, larger businesses relying on their Web presence must reach a level of "high availability", meaning a measurement of "five 9's" (99.999%). Without Network Monitoring, this is level is impossible to reach, even after expensive investments in load balancing and redundant systems.
High downtimes are not the only aspect threatening the success of an online presence; slow websites can also drive the customers away to your competitors' faster websites. This is the reason why performance monitoring is also very important.
To retain your existing customer base, as well as to attract new clients, you need to be aware of the problems with your site before the customers have to face them.
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Monday, August 21 2006
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.
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Thursday, August 17 2006
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
Most of theses issues can be felt when working directly on the system (e.g. using Remote Desktop), but maybe they do not have an impact on the server services they provide.
- fragmented disks
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Wednesday, August 16 2006
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):
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Tuesday, August 15 2006
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.
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Friday, August 11 2006
Article: "Keep An Eye On Your Applications"
On the website of "PROCESSOR" (Products, News and Information Data Centers Can Trust. Since 1979) there is an article about Application Monitoring which reviews the importance of Application Monitoring. They...
"...see the rise of application monitoring in the small to medium-sized enterprise space driven by the proliferation of the Web into extranets that tie together partners, customers, and buyers."
The products mentioned in the article tend to be on the costly side ($6000 and up), but you of course know that there is better priced option for Application Monitoring in IPCheck Server Monitor.
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Wednesday, August 09 2006
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.
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Tuesday, August 08 2006
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.
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Monday, August 07 2006
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.
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