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What is the difference between the protocol and commands used on default ports 8332 and port 8333?

From what I gather, port 8332 is the RPC port, it's "sensitive", only allowed by local host by default, and it has one username & password.

On the other hand port 8333 is some kind of P2P port that is used with Bitcoin transaction replication.

Can anyone clarify the official names, purposes, and security of each of these ports?

Which one uses JSON, and which is Binary?

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  • when i try to connect to my json rpc remotely i get the following errors port 8333: "RemoteDisconnected: Remote end closed connection without response" port 8332: [Errno 61] Connection refused any ideas if this is a firewall issue on my Ubuntu droplet or ?
    – Sonic Soul
    Aug 22, 2018 at 12:09
  • @SonicSoul not sure, I've left Bitcoin for the most part, pursuing technologies that won't consume as much electricity.
    – makerofthings7
    Aug 22, 2018 at 20:25

1 Answer 1

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The Bitcoin.org client will try to communicate to other nodes via port 8333 and those communications follow the Bitcoin protocol. If an explicit connection is given (IP address and port) the port setting can be overridden to use any port.

The bitcoin.org client can be configured to accept JSON-RPC communications, and when that is enabled will, by default, be on port 8332. Earlier versions of Bitcoin Core permitted this to be secured with SSL communications using the same port or a different port, however that capability has since been removed.

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    I would add that both ports are TCP (as opposed to UDP), and are listed in wikipedia: en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers
    – knocte
    Jun 27, 2016 at 12:43
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    SSL has been removed from Bitcoin since this answer was posted. It is now recommended to setup an ssh tunnel for encrypting the JSON-RPC connection.
    – alexg
    May 14, 2019 at 8:40

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