For discovering local devices, we have used a custom mDNS implementation based on raw BSD sockets - with the iOS 14.5 restrictions this is apparently no longer possible
That’s not true. The only change in this space in iOS 14.5 is that we now enforce local network privacy for BSD Sockets clients. If you follow the local network privacy rules (see the Local Network Privacy FAQ) your existing code should continue to work just fine.
I assume you mean it works fine if the multicast entitlement is applied? The problem is we provide an SDK for customers to embed in their apps so it would require each customer to apply for this entitlement - we have already tried to suggest this to affected customers but it is not ideal (e.g., customers end up in discussions with Apple tech support trying to convince them to use the modern non-BSD APIs, something they have no control over given the problem at hand).
If you insist on working with IP addresses then you take on the burden of implementing Happy Eyeballs, which is not fun (especially with UDP).
We have done just that and it is working fine (modulo the general iOS 14.5 hassle).
Coming back to your question about resolving a service, this is a known hole in the Network framework story right now (r. 73266838). There are two ways to get around this [...]
Thanks for the pointers, we will take a look! That is - do these APIs also require the multicast entitlement? We are only browsing for specific custom domains.
Ulrik
