Networking Q&A

Recently, the number of cybersecurity attacks has been steadily increasing. For corporate users, access is provided through special extensions that allow traffic from a specific application to be routed through a tunnel. However, connecting a device to an MDM solution is convenient for large customers, but it creates challenges for small companies and developer teams that need to secure their network connections (for example, when a specific application must be isolated so that all of its traffic is routed exclusively through the tunnel), or protect their local infrastructure by preventing external applications from establishing network connections to unexpected servers (for instance, some applications may make requests to random servers in an attempt to determine their network environment).

I'd imagine that RCS messaging is part of the package of excluded services when excludeCellularServices is set to true. Is that accurate? Documentation

When my URLSessionDelegate receives a server trust challenge (NSURLAuthenticationMethodServerTrust) and I respond with .useCredential for an enterprise self-signed cert, does the decision get cached for subsequent requests on the same URLSession, or is the delegate called again on every connection to the same host?

Hello, I filed feedback 22592307 around crashes my team and I are seeing in libquic now that we have adopted HTTP/3 for a large portion of our network usage. During the state of the union it was stated that libquic has been fully re-written in Swift by the WebKit team. Is that swift version the new implementation of libquic in iOS 27? If not, what will be the best way to adopt it without leaving the URLSession ecosystem?

Is the system default for this still false as of the OS 27 releases? When would you recommend setting it to true?

With iOS 27's improvements to seamless Wi-Fi/cellular transitions, is there guidance for apps and frameworks doing background network requests on how to handle a transition mid-request? Do in-flight URLSession tasks survive a network path change automatically, or should apps build their own retry logic?