apparation at Hogwarts

[Vanessa]

No: HPFGUIDX 27965

[snip whether or not Dobby's 'clap' was an apparation]

Is it possible that one can apparate WITHIN Hogwarts but not INTO it 
(i.e. not from Hogsmeade to Hogwarts, but you can go from the Great 
Hall to the kitchen)?
On reflection, this seems like such an obvious suggestion that I 
can't beleive it hasn't come up before...perhaps someone can point me 
towards the right messages in the past...