Demarc Security offers the opensource PureSecure, an all-inclusive network monitoring solution that allows you to monitor a network of servers from one powerful web interface. Feature summary:

• Multiple security level user based password protected website with a sliding window session idle timeout feature. Specific users can also be locked down to connecting only from specific IP ranges.
• Client/Server model network host/service monitor that allows for retrieving local host based status information remotely.
• Network Intrusion Detection System frontend for Snort with additions to the base functionality such as realtime analysis of network trends.
• Host Intrusion Detection System that checks all aspects of files/directories for signs of change including MD5 sum, uid, gid, mtime, etc. This service benefits tremendously from the client/server model because modifications for all hosts are stored on a central database which makes it much harder for intruders to wipe clean the telltale signs of their presence.
• Customizable email alerting for all subsystems based on any number of criteria such as designated priority, NIDS event signature, target hosts, and target services, with advanced functionality such as rate limiting alerts and restricting alerts to certain time periods.
• An auto-refreshing Mini-View window that can be kept in the corner of your screen all day and immediately alerts you to any network changes that might require your attention.
• Supported Operating Systems:
  • Linux
  • FreeBSD
  • OpenBSD
  • Solaris
  • NetBSD
  • WindowsNT
  • Windows2000
  • WindowsXP

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