Hi, thanks! Does your device have IPv6 connectivity to the wider Internet? That's a very good question. In all honesty I'm not too familiar with either iOS or networking, and given your point about the nslookup stack I'm going to go ahead and assume I probably don't have IPv6 connectivity no (your test code fails on the assertion for me, but then again I probably just don't know how to run a Swift app correctly). Thanks for clearing that out. That said, my use case is that I need to build an SNTP client with objective C as a hard requirement, and I need to offer an API that allows filtering addresses resolved from the chosen servers based on family. If the CFHost APIs are going to be deprecated, what would be the way to go?