Guard dogs good with children?

I am planning n a dopting a dog..and a child. I'm adopting a dog first because I need a companion but also protection but in a few years I plan on adopting an older child. I know they can be wary with strangers but if they can feel that I'm okay with the child and accept the child as not a threat we should be good right? I plan on adopting a doberman and later on a boxer what other dogs are ood for protection and great with kids? Age range: 8-10 year old