---
title: ifra_prefixmask
framework: Kernel
role: symbol
role_heading: Instance Property
platforms: [macOS 12.0+]
path: kernel/in6_aliasreq/3755265-ifra_prefixmask
---

# ifra_prefixmask

## Declaration

```occ
struct sockaddr_in6 ifra_prefixmask;
```