Advice from a trainer:
NOOOOOOOOOOOOOOOOOOOO!!! Don't do this to your dog!!! Most protective training is based on BREAKING your dog down and then building them back up to be aggressively protective!!! If you make your dog an indoor dog, you will be fine. Boxers are bred for gaurd work, so it is a gentic trait that they already have. Good OBEDIENCE training and being an indoor dog is all a Boxer really needs to be protective and to be supurb at it!!!
Average owners (99% of the pet owning population) does not have the control, knowledge of dog behavior or body language, or the correct reasons for having a dog protection trained or owning a protection trained dog. Please do not do this to your dog!!! Boxers do not do well as protection trained dogs in a family setting!!! If you are unmarried and without children, then consider a protection trained dog an excellent way to keep yourself that way as they are difficult to control or handle and can be volatile!!! If you have a wife and/or children, then reconsider this as children will easily irritate a protection trained dog (they are trained to have "short fuses") and the potential for a bad bite or worse is a definite possibility.
I have had several protection trained dogs (military working dog I adopted) and even as a trainer I had to limit my social life and who came to my house because I knew what/who my dogs would or would not put up with!!!
Why ruin a perfectly good dog!!!??? Not counting, Boxers are notorious for being naturally sneaky gaurd dogs. You can't hear them unless they WANT you to know they're there, They don't bark unless there is a NEED to, and they won't "attack" unless they have to protect themselves or their people!!!
Liz and Lilly