> For the complete documentation index, see [llms.txt](https://staderlabs.gitbook.io/ethereum/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://staderlabs.gitbook.io/ethereum/node-operator/permissionless-node-operator/node-registration-and-adding-validators/step-4-configure-stader-services/step-4.7-enable-doppelganger-protection.md).
# Step 4.7 Enable Doppelganger protection
### What is Doppelganger protect?
In Ethereum proof-of-stake (PoS), validators can face slashing if multiple validators operate with the same identity. Doppelganger Protection serves as a safeguard, preventing validators from being slashed and removed from the Beacon Chain in the event that a node operator unintentionally runs their validator keys on multiple machines simultaneously. [*Learn more*](https://lighthouse-book.sigmaprime.io/validator-doppelganger.html#:~:text=From%20Lighthouse%20v1.5.0%2C%20the%20Doppelganger%20Protection%20feature%20is,a%20validator%20running%20in%20a%20separate%20validator%20process.)
### How it works?
Whenever a validator client is restarted, Doppelganger protection intentionally skips 2-3 attestations. It actively monitors the network during this process to ensure that attestations are not being transmitted using your validator keys. Ideally, there should be no attestations, indicating that no other machine is utilizing your validator keys.
After the brief waiting period, the validator client will resume its regular validation operations. However, if it detects another machine using your validator keys, it will immediately terminate and generate an error message in its log files.
In most cases, doppelganger detection results in only a few missed attestations after restarting the client. However, when you're transferring your validator to a new machine or switching to a different Beacon client, doppelganger detection becomes essential to prevent accidental double attesting and potential slashing.
### **Doppelganger protection is optional.** You can choose Yes or No based on your preference
---
# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.
## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.
Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:
```
GET https://staderlabs.gitbook.io/ethereum/node-operator/permissionless-node-operator/node-registration-and-adding-validators/step-4-configure-stader-services/step-4.7-enable-doppelganger-protection.md?ask=&goal=
```
`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.