Whenever I attempt to log in to Lordaeron I get a message saying "You have been disconnected from the server.".
I played just a few hours ago prior to that.
I can log in normally to other realms such as Deathwing just fine, the problems seems to be only on Lordaeron (Which is the only realm I play on).
This problem does not happen to a friend of mine I was about to play with, so I assume it's a local problem.
Maybe the answer you need is on Warmane's Frontpage:
"Lordaeron is under a DDoS attack once again. It may take a few tries to successfully connect to the realm while we work to mitigate the impact and maintain the realm online."