Proof from teleportation

Proof from teleportation, also called proof against teleportation, was an abjuration spell that created a barrier to teleportation and dimensional travel.

Effects
The area protected by this spell was a sphere of radius 10 yd (9.1 m) per level of the caster that ignored impediments such as walls, floors, roofs, or other surfaces. For the duration of the spell, Astral travel by means of teleport, teleport without error, teleport dead, and dimension door was prevented from passing through the barrier in either direction. Use of a gate spell or other portal-generating magics were also prevented unless the spell resistance of the gating person was able to overcome the power of this spell each time a gate was attempted. Proof from Teleportation lasted a minimum of 10 hours (longer for more experienced casters) and could be dropped by the caster at any time, or by a successful dispel magic. Only powerful magics such as limited wish could overcome the restrictions on teleportation.

Travel by Ethereal means, such as vanish, armor of ethereality, ethereal jaunt, and the phasing ability of creatures like the phase spider were not prevented by this spell.

Components
In addition to verbal and somatic components, this spell required of granular material such as sand, salt, or sugar held in a 5 lb (2.3 kg) sack which was then dropped at the desired center of the spell effect.

History
This spell was published in "Volo's Guide to All Things Magical" and became generally known to the magical community.