How long should a salt be to make it infeasible to attempt dictionary attacks?

Question

I\'m designing an authentication system that works like the following:

1. User enters password
2. Salt is generated.
3. Password is hashed with whirlpool<

Answer 1

Book:

Cryptography Engineering: Design Principles and Practical Applications

by Niels Ferguson, Bruce Schneier, and Tadayoshi Kohno

21.2.1 Salting and Stretching

Since bits are cheap, for simplicity we suggest using a 256-bit salt.