FAQ: Understanding the Upcoming Ethereum Hard Fork


The Ethereum network will be undergoing a hard fork at block number 2463,000, expected to occur between 12:00 UTC and 13:00 UTC on Tuesday, October 18, 2016. https://fork.codetract.io/.

What should I do as a user?

Download the most updated version of your Ethereum client:

What happens if the hard fork isn’t taken?

If outdated Ethereum Clients are being used in time for the next hardfork, they will be synchronized with the pre-fork blockchain once the hardfork has been initiated. You will be locked on an incompatible chain based on the current Ethereum network rules.

Is it difficult to apply a fork in Ethereum-land?

A hard fork is an alteration to the underlying Ethereum protocol that creates improved rules. All Ethereum Clients must upgrade, or else they will stay on the incompatible chain which holds to the original rules. Due to the decentralized nature and convenience of use, implementing a fork is more difficult. Collaboration and communication are essential for a successful hard fork on a cryptocurrency blockchain. Having compatible Ethereum Clients is needed to guarantee a smooth transition.

What happens during a hard fork?

Once consensus has been reached on which changes should be included on a hard fork, the protocol changes are written to suit the various Ethereum Clients such as geth, Parity, and ethereumJ. A block number acts as the trigger for changes. Any Nodes that have not been upgraded to the newest rule set will still be in their old chains, where the old rules still apply.

Why do we really need a fork?

Since September 18 (UTC), an individual or group has been attacking the Ethereum network, causing delays in transactions. The network is currently packed with pending transactions, which is causing delays to users when processing their transactions. This can be seen as a DoS attack (denial of service) on the Ethereum blockchain.

An example of this is a transaction that results in a contract being assigned a price or fee for gas. Using the ADD operation is computationally less expensive than a more complicated process like encoding a number with SHA256. The attacker carried out a DoS attack by calling certain opcodes multiple times in their smart contracts. These opcodes are computationally hard for clients to process but very cheap to add to the network. To prevent attackers from filling up the network with low-cost contracts at high computational costs, some of the prices for operations are being raised.

Why are we making two forks? What will the consequences be?

Each of the hard forks deals with different issues that arose during the attack. The first hard fork is aimed at addressing network health issues related to low-cost opcodes. This is described as follows: Ethereum Improvement Proposal, “EIP 150 Hard Fork.” Block number 2463000 will witness the first hard fork. This will adjust the price for the undervalued opcodes that were used in the attack. The second fork is going to tackle other, less urgent issues, like the removal of empty accounts the attacker used as floodgates for the Ethereum network, which causes the blockchain’s size to increase. The second hard fork is still being discussed.

Once the second hard fork is in place, there may be another one. There may be delays or difficulties in processing transactions and synchronizing transactions until the state is completely cleared.

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