The IPFS network works in a pull-model, not push. So when nodes add content, they only add it locally. It's not until some other nodes request it, as it actually transfers.
So if you start a IPFS node locally, it won't get content pushed to it (well, some DHT data which is basically routing information, but not the content itself).
> ultimately, how can I know for sure that CloudFlare won't play the game where as acting as a proxy they will modify some of the files served?
You'll have to add some checks on your end for this as HTTP/browsers cannot provide these guarantees currently (maybe in the future?). So, download file A and add it to IPFS from your end. If you end up with the same hash, the content was not modified.
> isn't p2p file system like this all about trusting the network and not 1 server
Yes, IPFS <> IPFS is trustless as this verification happens automatically and the clients can verify content locally when it gets fetched. IPFS <> HTTP is harder as there is no functionality for doing this verification.
So if you start a IPFS node locally, it won't get content pushed to it (well, some DHT data which is basically routing information, but not the content itself).
> ultimately, how can I know for sure that CloudFlare won't play the game where as acting as a proxy they will modify some of the files served?
You'll have to add some checks on your end for this as HTTP/browsers cannot provide these guarantees currently (maybe in the future?). So, download file A and add it to IPFS from your end. If you end up with the same hash, the content was not modified.
> isn't p2p file system like this all about trusting the network and not 1 server
Yes, IPFS <> IPFS is trustless as this verification happens automatically and the clients can verify content locally when it gets fetched. IPFS <> HTTP is harder as there is no functionality for doing this verification.