Ethereum: RPC JSON outside of localhost


Here is an article about the issue you are facing when hosting Bitcoin Core JSON-RPC:

Ethereum: RPC JSON outside localhost, Bitcoin Core configuration issues

When running Bitcoin Core (BTC) as a server, it is not uncommon to encounter issues accessing JSON-RPC endpoints outside of your local machine. In this article, we will explore why this issue can occur and provide you with some solutions.

Why is this happening?

The issue lies in how Bitcoin Core handles RPC connections. By default, it listens on localhost:8333 (or 127.0.0.1:8333 for IPv4). However, when attempting to access a JSON-RPC endpoint outside of this local connection, Bitcoin Core will attempt to connect to ip_address:8333, where ip_address is a randomly generated IP address assigned by the system.

Configuring bitcoin.conf

Your Bitcoin.conf file looks like this:

testnet=1

server=1

daemon=1

listen = 1

Note that there is no option to specify an alternate IP address or port for JSON-RPC connections. This is the default setting and only applies to RPC connections.

Why doesn’t it work?

When you try to access a JSON-RPC endpoint outside of “localhost”, Bitcoin Core will use its internal IP address (or 0.0.0.0 in IPv4) as the target host and port number. This is because the default settings do not explicitly allow alternate hosts or ports.

Solutions:

You have a few options to overcome this issue:

  • Use ip_address:8333 instead of just 8333:

You can edit your Bitcoin.conf file to use the alternate IP address as specified in the JSON-RPC endpoint:

testnet=1

server=1

daemon=1

listen=0.0.0.0







Ethereum: rpc json outside localhost

listen on all available network interfaces

rpcip="192.168.1.100"

specify a different IP address

rpcport=8333

specify a port number


the rest of your configuration...

In this example, we use 0.0.0.0 to listen on all available network interfaces, and then specify the alternate IP address (192.168.1.100) for the RPC connection.

  • Use DNS-based configuration:

Alternatively, you can configure Bitcoin Core to use DNS-based access, which allows your computer to be resolved to its real IP address:

testnet=1

server=1

daemon=1

listen = 0.0.0.0

dns-addr="example.com"

In this case, you should make sure that the DNS record “example.com” resolves correctly.

  • Use a different JSON-RPC port:

If you are not concerned with listening for RPC connections and want to use a specific port number for the JSON-RPC endpoint (e.g. 8545), you can specify it in the Bitcoin.conf file:

testnet=1

server=1

daemon=1

listen = 0.0.0.0

rpcip="192.168.1.100"

rpcport=8545

Keep in mind that this will require changes to the JSON-RPC endpoint configuration that may not be necessary if you are using a different port number.

Conclusion:

If you want to resolve the issue of accessing Ethereum RPC endpoints outside of localhost using Bitcoin Core, consider one or more of the solutions above. By editing your Bitcoin.conf file or exploring alternative approaches, you should be able to resolve this issue and continue running your JSON-RPC server successfully.


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