Firewall is a project developing a firewall solution tailored for blockchain networks, aiming to counter smart contract exploits. Unlike conventional network firewalls that rely on predefined security criteria to monitor transactions, Firewall utilizes rollups for transaction aggregation and programmable transaction finalization rules to intercept exploits proactively. Its proof-of-exploit consensus mechanism identifies smart contract exploits as "invalid state transitions" for potential reversal, offering enhanced security for blockchain ecosystems.