Which of the following uses precomputed hashes to guess passwords?

Iptables is a utility for configuring firewall rules in Linux, used for network packet filtering, not for guessing passwords.

NAT tables store rules for Network Address Translation, which modifies IP addresses in network traffic, not for password cracking.

Rainbow tables are precomputed tables designed for reversing cryptographic hash functions, particularly for password cracking. They store a large set of precomputed hash values along with their corresponding plaintext inputs, allowing an attacker to quickly look up a given password hash and find its original password without needing to perform a brute-force attack.

ARP tables store mappings between IP addresses and MAC addresses for local network communication, not for password guessing.