Does "Dispel Magic" need a line of effect?

[0-hr]

I'm trying to make a refuge - some place I can sleep without mind flayers projecting in and grabbing my brain in the middle of the night. I figure that I will take a nice solidly walled keep (or cave)and fill it up with a "Forbiddance" such that the whole interior is under the effect, but it stops at the single doorway. Now, if that door is shut and there are no windows or such, is the Forbiddance vulnerable to being Dispeled by someone outside?

They can't see, or gain access to any area under the Forbiddance effect without opening the door. Can they still target the spell, or any part of it, with a Dispel Magic?

 

[Caliban]

I'm trying to make a refuge - some place I can sleep without mind flayers projecting in and grabbing my brain in the middle of the night. I figure that I will take a nice solidly walled keep (or cave)and fill it up with a "Forbiddance" such that the whole interior is under the effect, but it stops at the single doorway. Now, if that door is shut and there are no windows or such, is the Forbiddance vulnerable to being Dispeled by someone outside?

They can't see, or gain access to any area under the Forbiddance effect without opening the door. Can they still target the spell, or any part of it, with a Dispel Magic?

Dispel magic does need a line of effect.

However, nothing stops them from disintigrating (or otherwise destroying) the door and then casting dispel magic....

 

[Arravis]

The one thing Illithids dread above all else...
Undead and golums . Invest in both!