DHCP Sentry detects and alerts network administrators to the presence of rogue or unauthorized DHCP servers on their networks.

DHCP Sentry was created out of a need to detect rogue DHCP servers on residential networks in universities.  Typically, at a residential university, students are encouraged to share networking ports by purchasing hubs or switches.  However, in many cases students purchases routers or wireless router devices instead.  When these devices are incorrectly attached to the network, they can emit DHCP traffic and interfere with DHCP servers set up by the university.  This has the unfortunate effect of disconnecting many legitimate users from the networking services and causing headaches for network administrators. Microsoft has a tool called DHCPLOC which was supposed to help us with this issue but it suffers from horrible usability, no alert but an audible "beep", and a timestamp that only shows you the time of day.

DHCP Sentry helps administrators detect and resolve rogue DHCP issues by:

• Detecting rogue DHCP Servers
• Determining the MAC address of rogue servers for easier switch and port resolution
• Sending SMTP email or Instant Messaging alerts to administrators
• Throttling alerts as to not "spam" administrators
• Allowing admins to launch external programs to further act on alerts
• Allow admins to specify "authorized" DHCP servers as to avoid false positives
• Emits an audible "beep" during detection to alert anyone in the vicinity

Requirements:

• Microsoft Windows 2000/XP/2003/Vista
• .NET Framework 2.0
• Local Administrator privileges required

Cost:

• $30 USD