Here is an article about the problem Bitcoin Core is facing when running JSON-RPC:
Ethereum: RPC JSON outside of localhost, Bitcoin Core configuration issues
When running Bitcoin Core (BTC) as a server, it is not uncommon to encounter problems accessing JSON-RPC endpoints outside of the local machine. In this article, we will look at why you might experience this issue and provide some solutions.
Why is this happening?
The problem 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 you try to access the JSON-RPC endpoint outside of the local connection, Bitcoin Core tries to connect to “ip_address:8333”, where “ip_address” is a randomly generated IP address assigned by the system.
Bitcoin.conf Configuration
The 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 a default setting and only applies to RPC connections.
Why doesn’t it work?
When you try to access the JSON-RPC endpoint from anything other than “localhost”, Bitcoin Core uses its internal IP address (or 0.0.0.0 for IPv4) as the destination and port number. This is because the default settings do not explicitly allow alternate hosts or ports.
Solutions:
There are a few options to resolve this issue:
- Use “ip_address:8333” instead of “8333”:
You can modify your Bitcoin.conf file to use the alternate IP address specified in the JSON-RPC endpoint:
testnet=1
server=1
daemon=1
listen=0.0.0.0
listen on all available network interfacesrpcip="192.168.1.100"
specify another IP addressrpcport=8333
specify the 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 an alternate IP address (“192.168.1.100”) for the RPC connection.
- Use DNS-based configuration:
Alternatively, you can configure Bitcoin Core to use a DNS-based approach, which allows you to resolve the machine to its actual IP address:
testnet=1
server=1
daemon=1
Listen=0.0.0.0
dns-addr="example.com"
In this case, you need to make sure that the “example.com” DNS entry resolves properly.
- Use a different JSON-RPC port:
If you don’t care about listening for RPC connections and want to use a specific port number for your JSON-RPC endpoint (e.g. 8545), you can specify it in your Bitcoin.conf file:
testnet=1
server=1
daemon=1
Listen=0.0.0.0
rpcip="192.168.1.100"
rpcport=8545
Note that this requires modifying the JSON-RPC endpoint configuration, which is not necessarily necessary if you use a different port number.
Conclusion:
To resolve the issue of accessing Ethereum RPC endpoints outside of Bitcoin Core localhost, consider one or more of the solutions above. By modifying the Bitcoin.conf file or exploring alternative approaches, you will be able to resolve this issue and continue running your JSON-RPC server successfully.
