# vmnet_nat66_prefix_length_key The IPv6 prefix (uint64) to use with vmnet shared mode. ``` let vmnet_nat66_prefix_length_key: UnsafePointer ``` ## Discussion The prefix_length must be 64; the use of this key, `VMNET_SHARED_MODE`, is deprecated. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)