CISSP Domain 3 Security Engineering – Part 3 – Perimeter Defenses Cheat Sheet

Perimeter Defenses


Fences range from 1M to 2.4M with barbed wire on top and should be designed to steer ingress and egress to contolled points such as doors and gates.


Gates range from Class I gates (home) deter access and Class IV (airports,prison) gates designed to prevent cars from crashing through (ASTM F2200 Standard). They should be placed at control points at the perimeter.


A strong post (derived from short/strong posts used to tie ships to piers when docked) designed to stop a car. Usually placed infront of physically weak areas of a building, such as entryways.


Both a detective (allows guard to see) and deterrant (criminals favor poorly lit areas) control. Light should be bright enough to illuminate desired area.

  • Lumen – amount of light one candle creates; one foot candle is one lumen per square foot
  • Lux – 1 lumen per square meter


Closed circuit television (CCTV) is a detective control used to aid guards in detecting presense of intruders.

  • Infrared – see in the dark
  • Older Tube cameras are analog
  • CCD – Charged Couple Discharge – digital
  • Depth of field – The area in focus – more light larger depth of view, smaller aperture places more focus, wider aperture (low light) lowers depth of field
  • Field of view – the entire area viewed by the camera
  • Modes – fixed, autoscan, multiplex (multiple cameras feed into one display)
  • VHS,DVR (digital video recorder), NVR (network video recorder) – uses tcp/ip and allows centralized storage of video.


Preventative Physical security control, used on doors, windows to prevent unauthorized access. Can be mechanical, key locks, combination locks or electronic (smartcards or swipe)

Key Locks

Requires a physical key to unlock. The keys can be shared or copied (lowers accountability) and contains a combination based on bitting code. A common key lock is a “pin tumbler” lock which has two sets of pins, driver pins and key pins. The correct key makes the pins line up with the shear line allowing the lock tumbler to unlock.
“Ward or ward locks” must turn a key through channels (called wards); a skeleton key is designed to open varieties of warded locks.
A “spring bolt” lock is a locking mechanism that springs in and out of the doorjamb; the door may be closed with the spring bolt exposed. A deadbolt is rigid; the door cannot be closed when the deadbolt is locked. Both types of bolts extends into the strike plate in the door jamb.

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About the Author

Alfred Tong
Author and owner of this blog. A Networking enthusiast, full time networking and systems Engineer. Generally curious about all things IT.Certifications: GIAC GSEC, CCNP-S, CCNP, CCSP, CCDP, CCNA, RHCE, JNCIA - FWV