# Running Watchtower: for DePIN/Validator Node provider
The PoL Challenger Client Node is a DePIN Challenger node that participates in the PoL (Proof-of-Location) protocol and measures the location claims made by a DePIN Prover.
PoL Challenger Client Nodes can be run on community members’ laptops, desktops or even on cloud instances. As long as the node is running, there is a probabilistic algorithm (based on stake in the upcoming releases) that determines if the node will participate in a PoL challenge from the network.
Before a node can participate as PoL Challenger, it has to prove it's own capabilities (run a prover to prove it's own location - this mechanism is inbuilt in the challenger client container)
#### Prerequisites
Before you begin, ensure you have the following
* **Docker** (version 23.0.0 or above, refer: )
* **Instance** comparable to a t2 micro (**1 vcpu, 1GB RAM and 5GB harddisk**), though we recommend 2 cores, 4 GB RAM and 10 GB of storage.
## Running your Challenger client
{% hint style="info" %}
Explorer:
Our chain is gasless, so you do **NOT** have to fund either or the operator or challenger account with tokens.
{% endhint %}
### Key Points to consider before proceeding...
{% hint style="warning" %}
Note: For **EigenLayer** operators, it's important to maintain the distinction between Operator Key and Challenger Key. Refer the correct docs for setup as an EL operator [here](https://docs.witnesschain.com/infinity-watch/proof-of-location-mainnet/run-a-watchtower/eigenlayer-operators/running-a-pol-watchtower)
{% endhint %}
1. Generate a **dedicated watchtower key - ECDSA KeyPair** ( This [video](https://www.youtube.com/watch?v=ke9j2wuYhPE) demonstrates how you can use MetaMask to export one ). This will be used for registration & signing purposes.
2. **Ports to be opened if using public IP:**
```
Incoming ports to be opened (TCP & UDP ):
11112
22223
33334
33335
33336
44445
44446
44447
55556
Outgoing ports: Allow all
```
### 1. Registering the Watchtower Key
Download and install the *witness CLI:*
```bash
curl -sSfL https://witnesschain-com.github.io/install-dcl-cli | bash
```
After the installation is completed, register your watchtower key on WitnessChain's Layer 2 Chain: Use the KeyPair that you would have exported or created using Metamask or any other wallet.
witness-cli registerWatchtower --testnet --watchtower-private-key <your-watchtower-private-key-without-0x-prefix>
{% hint style="info" %}
**Why should I register?**
Registration helps with identification of your watchtower inside Witness Chain's watchtower network
{% endhint %}
### 2. Setting up the Watchtower keys and the config file
{% hint style="success" %}
Use ECDSA Keypairs
{% endhint %}
1. You can pass the required configuration to the docker container env via a file or directly with `-e` flag in the run command [(read more)](https://docs.docker.com/compose/how-tos/environment-variables/set-environment-variables/). Prepare a configuration file `watchtower.env` with the following entries as example shown below:
```bash
latitude=37.01511676489697
longitude=-79.0392271449855
country=US
region=Virginia
city=Ashburn
radius=1000
privateKey=
walletPublicKey=
keyType=ethereum
saveResultsInDatabase=false
submitResultsToContract=true
rpcUrl=https://blue-orangutan-rpc.eu-north-2.gateway.fm
projectName=
```
\
**Explanation:**
* ```
"latitude": 37.015, // Required. Latitude of the machine running the challenger client
"longitude": -79.039, // Required. Longitude of the machine running the challenger client
"country": "US", // Optional. Country in which the machine is located
"region": "Virginia", // Optional. State/Region in which the machine is located
"city": "Ashburn", // Optional. City in which the machine is located
"radius": 1000 // Optional. Accuracy in meters
```
* `privateKey` is your PoL signing key (Watchtower/Challenger Key)
* `walletPublicKey` is the wallet addresses where your contributions go
* `havePublicIPv4Address` (and `havePublicIPv6Address`) set them to **true** if you have a public IPv4 (or IPv6)
* `havePrivateIPv4Address` (and `havePrivateIPv6Address`) set them to **true** if you want to force the use of private IP
* `saveResultsInDatabase` saves the login, session, and challenge related data in a `.sqlite` file within the container
* `projectName` tags the watchtower with the project - examples include "spheron", "akash", "pingpong", "eigenlayer", etc. This is an optional field
### 3. Running the watchtower
Once you have the `watchtower.env` ready, the watchtower client can be started with
```sh
docker run -d \
--network=host \
--name pol-watchtower \
--env-file ./watchtower.env \
witnesschain/pol-multiclient:0.4-alpha
```
\
you can verify that the challenger is running by looking at the container status
```sh
docker ps
```
**Explanation**:
1. `docker run -d`: Runs the container in detached mode (in the background).
* ```
--network=host
Uses the host's network stack.
```
* ```
--name pol-challenger
Names the container as 'pol-challenger'.
```
* ```
--env-file ./watchtower.env
The container's environment is set using the attributes specified in 'watchtower.env' file
```
* ```
witnesschain/pol-multiclient:0.4-alpha: The name of the Docker image to run.
```
{% hint style="danger" %}
You may observe the following errors in the docker container
"registration is required on DCL contract. Please register your challenger publicKey:"
Don't worry, this is normal. if you [COMPLETE STEP 1](#id-1.-registering-the-challenger-key), these logs should disappear
{% endhint %}
## Post Setup
Once the setting up and registration is successful, you can check the logs from the challenger client ready for challenges. (`docker logs pol-challenger`). Congratulations, you are now a part of our DePIN family!
## Troubleshooting
As the only prerequisite is docker, make sure you are running atleast version 23.0.0 or above for the commands mentioned in the doc to work. \
\
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