Serving from across the table line

Hi sir, 

I've heard that it is illegal for the server to take position across the table line, while serving. I mean the server not staying behind the table; however, I can see in a match of yours, in which the opponent (Di Napoli) taking position beyond the table line while he serves the ball.

Is it a legal serve as far as he contacts the ball from behind the table?

I've added the link for reference, and  hope I'm able to make it clear to you. Sorry if I'm not using the appropriate term.

https://youtu.be/4gRqXwQjGcQ  

Watch @(2:51)

Hi John,

It is OK for the body to be past the line as long as the ball is behind.