Open Source Network Monitoring

The Best Features of Open-Source Network Monitoring Software

Computer networks have become the technological heartbeat of the world. The applications and the infrastructure of network computing is now a cornerstone of daily living.

The flexibility, the usability, and the vulnerability of a computer network demands management and monitoring. The methods, mechanisms, and procedures involved in network monitoring provide administrators with up-to-the-moment feedback concerning the current status of network activity, network performance conditions, and the long-term trends of network usage.

Modern network monitoring tools provide network administrators with extended features for testing and examining various network changes and services without having to go live among the existing user base. These tools come from all kinds of software development sources, including commercial software development companies, government organizations, individual users, and non-profit organizations. The price ranges from free for open source networking monitoring systems to extremely expensive commercial alternatives. This article will focus on free, open source network monitoring tools.

Types of Data Monitored and Collected

Before jumping headfirst into the requirements of open source network monitoring tools, let us take a glance at the types of data that a good network monitoring tool should monitor and collect. Expect to see several overlaps in the descriptions of the following network monitoring service areas.

Bandwidth Monitoring

Bandwidth is determined by the amount of electronic data that can pass along a given communications channel within a given period of time. Monitoring bandwidth permits an administrator to determine the actuality of connection speeds versus purchased connection speeds.

Bandwidth monitoring also enables a network administrator to determine the source of Internet usage from within the network. This is useful for isolating legitimate system usage from the malicious assaults of virus and hacker software.

  • An efficient bandwidth monitoring program will effectively test and store bandwidth information in an administrator controlled database. This type network monitoring tool is designed to include graphs and other visual aids during real time upload and download speed tests.
  • Additional reports include: identification of the adaptor type, packet error intelligence, and separation of upload/download bytes. Furthermore, an effective bandwidth monitoring service will also cover the average bandwidth speeds, peak bandwidth speeds, and roundtrip ping results.

Network Packet Monitoring

Though often a shared component of bandwidth monitoring software, network packet monitoring focuses mostly on the collection of information about the data that passes through the network connection.

For the purpose of error control and quality assurance, network data transfers are broken into manageable, limited sized chunks or packets of information. Packets contain identifying data that relates to the source IP address, the destination IP address, the overall size of the complete data project, the number of packets involved in a specific data transfer, and other useful information.

Networks, the Internet included, do not consist of a single point of entry or exit. When information is divided into many packets, the route from source to destination may vary from packet to packet. Packet headers provide the controlling network software with the information that permits the most efficient use of all available hardware components. Packet headers are also used to ensure that the final reassembly of the data is an accurate replica of the original source data.

Network packet monitoring seeks to analyze and decode the individual IP information for all individual packets on both local and remote systems. Accurate tracking of network packets provides the network administrator with precise packet related error reports. While packet monitoring helps to ensure accurate data transfer, it also helps the network administrator to identify network trouble spots.

Due to various types of network formats, network packets are also known by the following name tags:

  • Block • Cell • Frame • Segment

System Resource Usage

Network traffic originates from various sources. Some network monitoring software will include features that measure and record CPU usage, SQL activity, DNS server details, File Transfer Protocol activity, mail services, Internet activity, TCP services, file and folder size reports, and many other system usage specifics. All of these components of PC and network activity help the administrator establish checkpoints for network load balance and error correction adjustments. This can prevent network failures and irregularities.

An efficient network monitoring software will include automated administrator notification features. When errors are detected, the monitoring software should use multiple and redundant methods of notifying the administrator of the problems. This should include email, SMS, instant message pop-ups, and even pager services. Additionally, the monitoring software should be machine independent such that it can function without having components of itself installed on each system in the network.

Network monitoring software should be capable of multi-threaded packet checking. Many network monitoring packages also include bonus features such as the ability to check and perform the following hardware and system components and activities:

  • Printer availability;
  • The existences of files
  • File and folder sizes
  • CPU usage
  • Current system processes in use
  • Active users
  • Free Disk space
  • Disk partition data
  • SQL server storage support
  • Even the ability to automatically login and check session reliability.

A Look At Open Source Network Monitoring Software

Many open source network monitoring packages are a combination of small, single feature tools designed for specific functions within the overall network monitoring scheme. The resource link to SLAC that is listed at the bottom of this page will provide in-depth details and links for individual open source network monitoring software. But before getting there, here are a few of the various sub-divisions of network monitoring functions:

  • Application monitoring
  • Fingerprinting
  • Flow monitoring
  • Host based network monitoring
  • IP address management systems
  • Mapping Tools
  • Packet capture and analysis tools.

Many of these tools will overlap in their functions. As a rule, look for tools that include a graphical user interface. Also check out the availability of user forums, web-based support sites, and a reasonable documentation package. Examine the web sites. Search for reports on product weaknesses and virus problems.

Open source software is usually free but it may include some license restrictions. Make sure you read and understand the Terms Of Use agreement. Check for system compatibility.

Confirm that both the agent and the server components of the software are compatible to your operating system. Though some open source network monitoring software provides a Windows based agent, the server side of the software may be limited to an alternative operating system.

Some recommendations include:

  • Cacti: This web-based, open source package is good for collecting and graphing CPU load and bandwidth use.
  • Snort: Designed for intrusion detection, this free package with the availability of an upgrade to a purchased support package provides advanced security features.
  • Microsoft Network Monitor 3.4: Though not open source, this software is free from Microsoft and includes features for capturing, viewing, and analyzing network traffic.

For an excellent resource for open source network monitoring software details, Stanford University operates the SLAC National Accelerator Laboratory under a contract through the U. S. Department of Energy. Visit:

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