*`--trusted-block-root`: The consensus light client starts syncing from a trusted block. This trusted block should be somewhat recent ([~1-2 weeks](https://github.com/ethereum/consensus-specs/blob/dev/specs/phase0/weak-subjectivity.md)) and needs to be configured each time when starting the Nimbus Light Client Proxy.
*`--web3-url` - As the proxy does not use any storage, it needs access to an Ethereum JSON RPC endpoint to provide the requested data. This can be a regular full node, or an external web3 data provider like
A first requirement for the web3 data provider is that it must support the standard Ethereum JSON RPC Execution API, including the [eth_getProof](https://eips.ethereum.org/EIPS/eip-1186) call.
The latter is necessary to validate the provided data against the light client.
A second requirement is that data served from provider needs to match with
the ```--network``` option configured for the Nimbus Light Client Proxy. By default the light client proxy is configured to work on mainnet. Thus, the configured provider needs to serve mainnet data.
On the [beaconcha.in](https://beaconcha.in) website ([Goerli](https://prater.beaconcha.in)), navigate to the `Epochs` section and select a recent `Finalized` epoch. Then, scroll down to the bottom of the page. If the bottom-most slot has a `Proposed` status, copy its `Root Hash`. Otherwise, for example if the bottom-most slot was `Missed`, go back and pick a different epoch.
To start the proxy for the Goerli network, run the following command (inserting your own trusted block root and replacing the web3-url to your provider of choice):
```bash
# From the nimbus-eth1 repository
TRUSTED_BLOCK_ROOT=0x1234567890123456789012345678901234567890123456789012345678901234 # Replace this
### Using the Nimbus Light Client Proxy with existing Wallets
The Nimbus Light Client Proxy exposes the standard Ethereum JSON RPC Execution API and can thus be used
as drop-in replacement for any Wallet that relies on this API.
By doing so, it turns an untrusted web3 data provider into a verified data source.
The Nimbus Light Client Proxy has been tested in combination with MetaMask.
The [MetaMask configuration page](./docs/metamask_configuration.md) explains how to configure the proxy, and how to configure MetaMask to make use of the proxy.
### Update and rebuild the Nimbus Light Client Proxy