These flags are set in zedit, and are global for the whole zone.
CLOSED - Players cannot enter the zone.
NO_IMMORT - Immortals (below LVL_GRGOD) cannot enter the zone.
QUEST - Currently unimplemented.
GRID - Only zones 'on-the-grid' are shown on the areas command
NOBUILD - Locks the zone so that it cannot be edited. Can be unlocked only by
a GRGOD, IMPL, or someone in the zone's builders list.
NOASTRAL - Prevents teleportation magic from working to or from this zone.
See also:: ZLOCK, ZUNLOCK, ZEDIT-MENU