user675: Will nodes still be able to find each other using today's official Bitcoin client?

user10377: I'm inclined to believe that a successful fracturing of the network (truly partitioning it) would effectively fork the Blockchain, and create two or more separate Blockchain universes, depending upon the number of successful partitions were achieved. If it hasn't been performed already, I would expect some academic institution might try experimenting with small isolated Bitcoin networks or enclaves and slowly break the connectivity between enclaves to see what the behaviors really unfold. The point about TOR (The Onion Router) is a great one because it is likely to route around any censorship and possibly prevent the forking of the Blockchain provided there is enough network redundancy using TOR.

user9790: Very few nodes run on ports other than the default of 8333, so if somebody had unilateral control of every network connection in the world and decided to block 8333 then Bitcoin would collapse. There's portions of the network that use Tor for communication only, and these would not be affected by port 8333 being blocked at all. 

user4708: The core developers could decide on a new port then get the word out that everyone should start using that port.  It's a very easy change in the bitcoin.conf file.  Mining pools, online wallets like blockchain.info and Coinbase, and "light" wallet providers like Electrum could lead the way.  (For example, once blockchain.info made the port change on their server, all their users would automatically have service again).  I think it would recover quite quickly.
The new port could also be shut down but it would turn into a game of "whack-a-mole".  The developers would probably come out with a new release that used some kind of strategy to dynamically search for a port to use to solve the whack-a-mole problem.
Alternatively, there is no reason they could not just switch to using port 80 for bitcoin.  The main disadvantage is it would make it a bit more complicated to run a web server and bitcoin node on the same machine.

675: <p>Will nodes still be able to find each other using today's official Bitcoin client?</p>
 10377: <p>I'm inclined to believe that a successful fracturing of the network (truly partitioning it) would effectively fork the Blockchain, and create two or more separate Blockchain universes, depending upon the number of successful partitions were achieved. If it hasn't been performed already, I would expect some academic institution might try experimenting with small isolated Bitcoin networks or enclaves and slowly break the connectivity between enclaves to see what the behaviors really unfold. The point about TOR (The Onion Router) is a great one because it is likely to route around any censorship and possibly prevent the forking of the Blockchain provided there is enough network redundancy using TOR.</p>
 9790: <p>Very few nodes run on ports other than the default of 8333, so if somebody had unilateral control of every network connection in the world and decided to block <code>8333</code> then Bitcoin would collapse. There's portions of the network that use Tor for communication only, and these would not be affected by port 8333 being blocked at all. </p>
 4708: <p>The core developers could decide on a new port then get the word out that everyone should start using that port.  It's a very easy change in the bitcoin.conf file.  Mining pools, online wallets like blockchain.info and Coinbase, and "light" wallet providers like Electrum could lead the way.  (For example, once blockchain.info made the port change on their server, all their users would automatically have service again).  I think it would recover quite quickly.</p>

<p>The new port could also be shut down but it would turn into a game of "whack-a-mole".  The developers would probably come out with a new release that used some kind of strategy to dynamically search for a port to use to solve the whack-a-mole problem.</p>

<p>Alternatively, there is no reason they could not just switch to using port 80 for bitcoin.  The main disadvantage is it would make it a bit more complicated to run a web server and bitcoin node on the same machine.</p>
