[aasma]

Barking is a complicated set of behaviours that perform a myriad roles. Dogs will bark at strangers as well as at creatures that move fast and yes, even at other dogs. There are many dogs who bark with the intention simply to shout "hello," and the situation the frequency, intensity, and context of your dog's barks are crucial elements in determining the reason your dog is compelled to speak.  Also Read i got a dog and i hate it

[JeanMcaleer]

It's completely normal for dogs to bark at other dogs. They communicate this way, and it can mean various things. As you mentioned, some dogs bark as a way to say "hello" or to alert their owners to something unusual.
The frequency, intensity, and context of your dog's barks can provide insights into their motivation. If you want to understand your dog's barking better, you can read more about it in the article about Why do dogs love tennis balls. It might help shed some light on this behavior.
Remember that training and socialization can also play a significant role in reducing excessive barking.