IP Blocklist Policy | MuleSoft Documentation
# IP Blocklist Policy
**Policy Name** | IP Blocklist  
---|---  
Blocks a single IP address or a range of IP addresses from accessing an API endpoint  
Security  
**First Flex Gateway version available**  
**Returned Status Codes** | 403 - IP is rejected  
## Summary
The IP Blocklist policy controls access to a configured API endpoint from either a single IP address or a range of IP addresses.
The IP Blocklist policy restricts access to a protected resource when a match is found between a source IP (specified when configuring the policy) and either a list of individual IPs or a range of IPs. The policy supports both IPv4 and IPv6 addresses.
DataWeave 2.0 expressions define the source IP to be used when the policy tries to determine whether the IP belongs to the restricted IP list defined in the policy.
## Configuring Policy Parameters
### Flex Gateway Local Mode
In Local Mode, you apply the policy to your API via declarative configuration files. Refer to the following policy definition and table of parameters:
```
- policyRef:
  name: ip-blocklist-flex
 config:
  ips: <array> // REQUIRED
  ipExpression: <string> // OPTIONAL, default: "#[attributes.headers['x-forwarded-for']]"
```

Parameter | Required or Optional | Default Value | Description  
---|---|---|---  
The list of IP addresses blocked from the API. You can define one IP or IP range at a time, as many times as required. For more information, see Specifying IP Addresses to Blocklist in the Policy.  
`ipExpression` |  `#[attributes.headers['x-forwarded-for']]` |  The DataWeave 2.0 expression to be used for extracting the IP address from this API request  
#### Resource Configuration Example
```
- policyRef:
  name: ip-blocklist-flex
 config:
  ips:
   - "192.168.1.1"
   - "192.168.3.1/30"
   - "192.168.2"
   - "192.160"
```

### Managed Flex Gateway and Flex Gateway Connected Mode
When you apply the policy to your API instance from the UI, the following parameters are displayed:
Parameter | Description  
---|---  
IP expression |  The DataWeave 2.0 expression used for extracting the IP address from this API request.  
The list of IP addresses blocked from the API. You can define one IP or IP range at a time, as many times as required. For more information, see Specifying IP Addresses to Blocklist in the Policy.  
Method & Resource conditions |  The option to add configurations either to a select few or to all methods and resources of the API.  
## Specifying IP Addresses to Blocklist in the Policy
Specify IP addresses to block in your policy based on:
  * The IP address of the request.
  * The origin IP address that is determined by resolving a specific DataWeave expression, such as the x-Forwarded-For header.
  * Any other origin.


### Blocklist Access Based on the IP Address of the Request
Blocklist access based on the IP address of the request in any of the following ways:
  * Define a specific IP address by enumerating it in the white space, for example, `192.168.1.1`.
  * Define a subset of addresses by identifying a subnet mask, for example, `192.168.3.1/30` includes the consolidated range `192.168.3.0` through `192.168.3.3`.
  * Define a whole range of IP addresses by specifying the relevant octets of the IP address that you want to permit, for example, setting `192.168` will include IP addresses from `192.168.0.0` through `192.168.255.255`.


### Blocklist Access Based on the Origin IP Address of the x-Forwarded-For Header
If the client connects to your API through an HTTP proxy or a load balancer, you can blocklist the client’s specific IP address (the IP address originating the request) instead of the address that appears in the request
For example, if you want to blocklist `192.168.2.3` and the address of a client connecting through an HTTP proxy is `92.40.1.255`, the client requests appear with the public address using the proxy.
Typically, applications use the `X-Forwarded-For` header to identify the origin IP addresses of a request that was redirected to your endpoint.
You can use a DataWeave 2.0 expression in the policy to instruct the service to look for the IP address in the `x-Forwarded-For` header.
When you insert the IP address in the IP expression field of the policy parameters, Anypoint Platform is instructed to look for the starting IP address in the concatenated values of the `x-Forwarded-For` header of the request.