Grey Box Testing: Combination of white box and black box testing
Red Box Testing: It is nothing but a Protocol testing
Grey Box Testing: Combination of white box and black box testing.
Red box testing - User / Client can apply any techniques to accept the project. They will apply white box or grey box or black box for accepting the project. So we are calling the user acceptance testing as a red box testing. Also networking, peripherals testing and protocol testing called red box testing.
Yellow box testing ? It is a message level testing. Simply yellow box testing is checking against the warning messages. Weather the system properly throwing the warning messages or not?