> ## Documentation Index
> Fetch the complete documentation index at: https://optimism-373f39ad-soyboy-docs-op-supernode-guide.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Legacy Geth configuration

> Learn how to configure Legacy Geth for serving historical execution traces on upgraded OP Stack networks.

Legacy Geth (`l2geth`) is the old pre-Bedrock OVM client running against a preconfigured data directory.
It is required only for upgraded networks like OP Mainnet to serve historical execution traces from before the Bedrock upgrade.
If you're running a node that had a chain genesis after the Bedrock upgrade, you do not need Legacy Geth.

<Info>
  Legacy Geth (`l2geth`) is the pre-Bedrock OVM client and is unrelated to op-geth's deprecation. l2geth is required on OP Mainnet archive nodes regardless of which post-Bedrock execution client you run (op-reth or op-geth).
</Info>

<Info>
  If you need state proofs for post-Bedrock blocks (for example, for withdrawal proving), see the [historical proofs config](/node-operators/reference/op-reth-historical-proof-config) — that's a different feature.
</Info>

## Do you need Legacy Geth?

Only requests for *historical execution* — RPC methods that need to execute pre-Bedrock transactions rather than just read data from the database, such as `eth_call` and the `debug_trace*` methods — are routed to Legacy Geth.
Everything else will be served by your execution client directly.
If you do not need these RPC methods for pre-Bedrock blocks, then you do not need to run Legacy Geth at all.

For the exact lists of which RPC methods are routed to Legacy Geth and which are served by your execution client, see the [Legacy Geth configuration reference](/node-operators/reference/legacy-geth-config#historical-execution-vs-historical-data).

## Setup

### 1. Download the preconfigured data directory

Download and extract the Legacy Geth data directory, which is available at [datadirs.optimism.io](https://datadirs.optimism.io).

```bash theme={null}
# Download the data directory
curl -o legacy-geth-datadir.tar -sL <URL-to-legacy-datadir>

# Extract it
tar -xvf legacy-geth-datadir.tar -C /data/legacy-geth
```

### 2. Configure Legacy Geth

Run Legacy Geth with the minimum required configuration:

```bash theme={null}
USING_OVM=true \
  ETH1_SYNC_SERVICE_ENABLE=false \
  RPC_API=eth,rollup,net,web3,debug \
  RPC_ADDR=0.0.0.0 \
  RPC_CORS_DOMAIN=* \
  RPC_ENABLE=true \
  RPC_PORT=8545 \
  RPC_VHOSTS=* \
  geth --datadir /data/legacy-geth
```

<Warning>
  It is imperative that you specify the `USING_OVM=true` environment variable.
  Failing to specify this will cause `l2geth` to return invalid execution traces or panic at startup.
</Warning>

The full set of environment variables Legacy Geth accepts, with defaults, is catalogued in the [Legacy Geth configuration reference](/node-operators/reference/legacy-geth-config#environment-variables).

### 3. Configure your execution client to route to Legacy Geth

Both op-reth and op-geth use the same `--rollup.historicalrpc` flag to route pre-Bedrock execution requests to Legacy Geth.

<Tabs>
  <Tab title="op-reth">
    ```bash theme={null}
    op-reth node \
      --datadir=/data/optimism \
      --rollup.historicalrpc=http://localhost:8545 \
      # ... other flags
    ```
  </Tab>

  <Tab title="op-geth">
    <Warning>
      **op-geth has reached end-of-support (2026-05-31) and does not support the now-active Karst hardfork.** New deployments should use op-reth. See the [op-geth deprecation notice](/notices/op-geth-deprecation).
    </Warning>

    ```bash theme={null}
    geth \
      --datadir=/data/optimism \
      --rollup.historicalrpc=http://localhost:8545 \
      # ... other flags
    ```
  </Tab>
</Tabs>

The `--rollup.historicalrpc` flag tells your execution client where to route requests for historical execution.

## Troubleshooting

<Warning>
  `l2geth` is based on an old version of geth where trace functionality is unstable.
  It is no longer maintained and will not be updated.
</Warning>

### Legacy Geth won't start

**Problem**: `l2geth` panics or returns errors on startup

**Solution**: Ensure `USING_OVM=true` is set in your environment variables

### Invalid execution traces

**Problem**: Legacy Geth returns invalid or incorrect trace data

**Solution**: Verify that `USING_OVM=true` is set and the data directory is complete and uncorrupted

### Execution client not routing to Legacy Geth

**Problem**: Historical execution requests are not being routed to Legacy Geth

**Solution**: Check that `--rollup.historicalrpc` is set on your execution client (op-reth or op-geth) with the correct URL to Legacy Geth