Bitcoin Forum

If a wallet is down except for a few hours each week to catch up the block chain, is the wallet's IP address associated with that wallet's  transactions?  Can others associate a wallet's receiving address with its IP address?

It is more easily for observer to correlate IP nodes with transactions if wallet is only online while transaction is made vs wallet that is online 24/7

Use Tor if You should need to be paranoid.

If someone hacks into your computer or you acquire a virus, trojan, or other malware, then they can potentially determine all addresses that are stored in any wallets on that computer regardless of whether you run the client or not, as well as all addresses associated with any web based wallets that you connect to as well.

If you are just asking about someone monitoring the internet traffic going to and coming from your computer, then an address can only be associated with an IP when sending a transaction.  There is nothing in the client that announces your addresses to the network when you aren't sending transactions regardless of whether you are receiving bitcoins or just sitting there forwarding transactions and blocks.

You are making a common misunderstanding of how Bitcoin works.

The Bitcoin client collect IP addresses and the Bitcoin blockchain doesn't store them.  From the data in the blockchain there is no way to associate a transaction to an IP address or to know which node is responsible for mining each block even.

This misunderstanding comes from the information collected and reported on the third-party service, Blockchain.info.  They have a backend that makes many connections (over 3K at present).  When a node that blockchain.info's backend is connected to is the first they know of to see a transaction then their service tags that transaction with that node's IP address.    But there are tens of thousands (or more) peer nodes on the Bitcoin network so very often this "first relayed by" node IP address information is inaccurate.  If your node does not accommodate incoming connections, then quite often the transactions your node makes will be reported on Blockchain.info as having been "first relayed by" with some other IP address than your own.

This same IP monitoring is part of the approach that Blockchain.info uses to try to determine which node (mining pool) is responsible for solving a block.  And that's why there is a sticky at the top of the mining forum board.  An excerpt from that sticky:

It wouldnt matter IP's can only lead to cities at best.

Well, thats until the ISP gets a subpoena, then they lead to full name's & addresses.

But IPs aren't even stored in the blockchain

Already been said in this discussion:

IPs aren't stored in the blockchain, but it's possible for someone to observe the network and correlate your IP with a given address.

Possible? Perhaps.

But you can only tell while as they broadcast a new transaction to send bitcoins, and you'd have to have a lot of control over the connections that your target's client is making.  If you can't guarantee that you can see ALL of your target client's connections, how would you tell the difference between a transaction that your target is relaying (after receiving it from somewhere else) or initiating? And if you can do that, then it isn't going to help to shut down the client when you aren't sending transactions, since no useful information for correlating an address to the IP is sent during that time anyhow.

Right. It's possible, but it would be difficult and prone to error.

Actually there are a number IP databases that can reverse an IP to and address.  I worked for a company that used them once.  Basically when you make a transaction where you give an address, they can sell that information IP --> Address.

The bigger concern for tracking your address used to make payment with BitCoins.  That can be tracked and tied to you.  if you received or spent BTC that can be traced and if you hold an account any place where your contact information is stored, at an exchange or somewhere you did business it can be tied back to you.