[SYMBOL] [A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [Z] objects enumerating modifying referencing searching octets subnetting on/off octet boundaries off-site name server opcodes optimizing zones options dig nslookup org domain origin, zone datafile outages 2nd |