Dogs get to know each other through scent before all. The way of approaching may indicate dog's intentions. If dogs do not know each other, the best and least aggressive way to approach is arched, not in straight line and without eye-contact. After that, they will get to know each other by scent, sniffing each others glands, located under the tail.
Next, you should pay attention to head, ears and tail positioning, since depending on the signals they get through meeting, they can become submissive, dominant, dominant-aggressive, confident as well as indifferent.
Encounter of two dominant dogs
When two males of similar or equal dominance meet, where none of them is threatening, usually the greeting dance occurs. They slowly approach each other sideways, avoiding direct eye-contact, but in dominant posture: calm and with raised tails. They sniff each other's anal region. After this, they may circle around each other for a few times and then usually go their own way. However, since there is a lot of charge when meeting, it does not mean that the fight will not occur due to some dominant signals and the attempt to dominate.
It happens very often that the one that attacked did not show dominant signs but uses the attack as an answer to other dog's dominant signals. Humans always judge a dog that did the attacking because they do not know to read the signals of a dog that causes a conflict.
Except that, very often it can come to competition in scent marking, when if one specimens comes upon urine of a rival, it "wipes" it out with its own and, by doing so, denies the opponent's ownership.
Encounter of an aggressive and a dominant dog
Approaching snout to snout, making eye-contact, vocalization – are all elements that cause or indicate aggression. Any dominant dog will react to it. Even two dogs that know each other will in such case react instinctively and clash if any of them decides that the other one is coming aggressively.
If a dog already stands sideways to approaching dog, and it responds to such approach by turning towards the newcomer – it is a sign of its confidence and its disapproval of dominance over it. Whether there will come to a conflict or not depends on the approaching dog, but, above all, the reaction of a owner that should call for it.
Encounter of a dominant and submissive dog
Submissive dog will approach the dominant one with lowered body position and with ears set back. Very often it will run to it with wide tail wagging, whining, nudging snout to snout. If it lowers its back part of the body and raises the front accompanied by licking the dominant dog or the air in front of it – it emphasises its submissiveness. Then, the dominant dog will sniff rear end of the submissive one, while the other will stand or lie on its side or back.