Paessler Blog
Archive for "08/2006"
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-25
Directory Traversal Vulnerability Issue Fixed for IPCheck Server Monitor
We have published a new version of IPCheck Server Monitor that fixes a security issue in the webserver: By Using URLs with special characters a so-called "directory traversal" was possible. This fact could be exploited to gain access to files on the disk which IPCheck is installed on.2006-Aug-24
Easy to read Drawings of IP, TCP and UDP Packet Headers
This is some quite technical information, but it may help you to understand the foundations of everyday networking. Matt Baxter has some drawings that will show you how the structure of the headers for IP, TCP, UDP and ICMP looks byte-by-byte. It is just the normal information from the RFCs presented in an easy to read format.
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-16
The art of network troubleshooting
Grag Schaffer has published an article on computerworld.com about his approach to network latency hunting and troubleshooting. Makes a nice reading over lunch.While the technology has changed, the basic methods for troubleshooting networks really haven't. Sure, there are fancier sniffers, analyzers and monitors, but the real basics that demand an understanding of networking to the core level remain the same. Let me present a case history from the days of Thinnet to illustrate.
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-14
Using Multiple-Host-PINGs to monitor the performance of a WAN connection
The basic idea of this new custom sensor for IPCheck Server Monitor is that in many cases sending PINGs over a WAN connection to just one device is not a very reliable means of testing the connection. Every once and a while you will see dropped packets due to network overload, server trouble or whatever. On WAN connections you never know what happens between you and the server. Thus when monitoring just one distant system a number of lost PINGs don't tell you too much about the performance of the connection inbetween.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.
2006-Aug- 2