Depends on the launcher. Not all of them retain your login creds and connection to the login server. Also the reconnection is not automatic. You have to select your character manually and you have to manually click play to connect to the server manually. Most of that happens in Rohan too, except for a few restricted places. As I said, Rohan is 10 years old. In some of the newer dungeons and instances it won't drop you into the starting point for that dungeon/instance. You will be dropped at the last registered bind - if you bothered to set it close to where you DC'ed. But there is no auto-reconnect in any MMO that I know of.