how hot should my rear be?

No this isn't a *** rated question. How hot should your rear get with normal driving? I took my car out for about 15 miles and brought it home and put it on the lift. The rear end was hot enough that I couldn't hold my hand on it. As I worked my way down the axle tubes it got better. I can't say I have ever done this before so I don't know how hot is acceptable but this seemed to hot to me.