Rottweiler ownership should be entered into with the knowledge that it brings responsibility as well as pleasure.  Always be aware that a Rottie, if uncontrolled and not carefully trained, can be a danger.  For example, just by jumping up on a child, an older person or someone not in prime health, a Rottie can, without meaning to, knock down or hurt the person.

Obedience training along with socialization, therefore, is a must from puppyhood.  The dog's protective instincts must be properly channeled to make him steady and reliable and completely, instantly controlled by your voice.   From the age of just a few months, get him to know the commands "come", "down", "stay", "heel", and "sit".  Make a game of doing so, with lots of petting and praise when the order is correctly followed and you will be surprised how quickly your extremely intelligent baby Rottie will get the idea.  Rottweilers are smart and they love to please - therefore they are generally quite easily trained.

Once the puppy is six months old, take yourself and your Rottie to join a training or obedience class for his more formal training.  It is usually more fun working with a group than alone.

Rottweiler's are instinctively guard dogs, having been used for this work throughout the ages.  It has been said that even as far back as the days of Emperor Nero, there were always several progenitors of the modern Rottweiler on guard around his palace, and this tendency has been nurtured over the years in Germany and elsewhere.  Our modern Rottweiler's take their own and their master's possessions with deep seriousness.  Careful handling of this instinct is essential if problems are to be avoided.  This is where socialization takes on special importance.   For while you may want your Rottweiler to protect you, your home and your property, at the same time you want him to realize that certain people (friends, family members, letter carriers, etc.) also have legitimate business there and should be able to come and go unmolested.  So take the trouble to "introduce" your Rottie to these people.  Let your Rottie see that you consider them friends and approve of their presence and he will react accordingly, being at least more tolerant of their presence.

If you must leave your Rottie in the care of strangers, make sure that he gets to know and accept these people before you leave.  Rottweilers are not likely to bite without provocation; they are fare more subtle, as anyone can tell you who has found himself allowed to enter a house or room by the attending Rottweiler, but then is not permitted to leave and is just held there by the dog's belligerent attitude until someone he trusts returns home and authorizes freedom.  This is quite effective since most people dare not "cross" an obviously hostile animal of this size.  But if you have indicated by your attitude that a person is a friend, your Rottie will very likely follow suit.

Reference:    Rottweilers by Anna Katherine Nicholas    #1 Best Selling Rottweiler Book