---
title: subnetMasks
framework: networkextension
role: symbol
role_heading: Instance Property
path: networkextension/neipv4settings/subnetmasks
---

# subnetMasks

The IPv4 network masks to assign to the TUN interface.

## Declaration

```swift
var subnetMasks: [String] { get }
```

## Discussion

Discussion Each mask in this array is combined with the IP address in the corresponding index in addresses to specify an IPv4 network that the TUN interface is (virtually) connected to.

## See Also

### Accessing IPv4 properties

- [addresses](networkextension/neipv4settings/addresses.md)
- [router](networkextension/neipv4settings/router.md)