This article was written by Logical on reddit.com/r/Bitcoin/
The whole B2X attack is based on tricking wallets into thinking it is a valid chain. B2X intentionally removed all replay protection; it changed its code so that it would mimic the signals from core nodes and its collaborators intend to pass it off as bitcoin on their services.
The core developers are creating countermeasures to ensure that core nodes continue to work on the peer to peer level. If you want to transact after the fork on the bitcoin blockchain run a bitcoin core node.
If you don’t need to transact soon after keep your private keys somewhere safe.
If you are using a light wallet to send or receive you may get screwed. People may send you B2X coins and your wallet won’t know the difference.
As always, don’t have your coins in exchanges – those are actually the exchange’s coins and the Exchange has a liability to you, but coins on exchanges are not yours ever.
Also, remember who acted to protect the system in which you are keeping your money and who acted to jeopardize the system in which you are keeping your money. The NYA supporters know that there is no consensus behind their proposal. More companies have abandoned the agreement than joined it since it was announced and hundreds of companies and organizations, including user groups from all over the world have denounced the NYA. That they continue to move “full speed ahead” with a contentious deployment, intentionally engineered to jeopardize your money should be a sign to any level headed person that the NYA backers are reckless. While they will not succeed with this attack, they must not be forgiven after they fail. If you trust them in the future you are taking a reckless risk with your money. I myself will boycott all businesses supporting the New York Attack so long as the current presidents of them hold any shares in those companies.