Several hours after the start of a mac with macOS BigSur, I am unable to access www apple com. Thid creates a lot of problems. I spent a lot of time exploring what the cause could be. DNS state when the problem does not manifest itself Whenever I restart the mac, the problem disappears. Looking as dscacheutil, I can see both IPv4 and IPv6 are being populated. $dscacheutil -q host -a name www.apple.com name: e6858.dscx.akamaiedge.net alias: www.apple.com www.apple.com.edgekey.net www.apple.com.edgekey.net.globalredir.akadns.net ipv6_address: 2a02:26f0:7400:1ac::1aca ipv6_address: 2a02:26f0:7400:1ad::1aca name: e6858.dscx.akamaiedge.net alias: www.apple.com www.apple.com.edgekey.net www.apple.com.edgekey.net.globalredir.akadns.net ip_address: 2.21.169.157 DNS state when the problem does manifest itself After a few hours and a sleep of the mac, I cannot access www apple com in any way. $dscacheutil -q host -a name www.apple.com name: e6858.dscx.akamaiedge.net alias: www.apple.com www.apple.com.edgekey.net www.apple.com.edgekey.net.globalredir.akadns.net ipv6_address: 2a02:26f0:7400:1ac::1aca ipv6_address: 2a02:26f0:7400:1ad::1aca So IPv4 addresses are not populated at that point. I noticed that apple com itself (without the www) can be pinged. And indeed the dns resolution has IPv4 populated : $ dscacheutil -q host -a name apple.com name: apple.com ip_address: 17.253.144.10 This is on a network that supports only IPv4, not IPv6. Running “sudo dscacheutil -flushcache ; sudo killall -HUP mDNSResponder” or rebooting the router does not fix the issue. - Only rebooting the mac fixes the issue. dig correctly returns both IPv4 and IPv6 addresses. Can anyone help me in any way understand the problem?

How can I exchange information easily and securely between 2 apps on macOS? 1 of the app will infrequently request a short amount of data from the other one. Here are the options that I can see: DistributedNotificationCenter : very easy to implement. However, the notifications are broadcast to any apps that wants to listen to it, and apple's documentation clearly states that it's not secure. I would ideally like a mechanism that is as simple as this, but with a secure communication between 2 aps Apple Events. I am not sure how to make an app respond to apple event. And I think it would be the same problem : any other app could talk to these 2 apps and get information from them. I ideally want this to be more secure. XPC, this seems overly complex for what I want to do, as my understanding is that this essentially involves creating a third process that will regulate communication. Implementing IPC via sockets. It seems reasonable I think, as I can probably secure the communication better. However it feels over-enigneered to set up sockets that always listen for incoming connections, etc Am I missing a simple mechanism on macOS that could help me in that use case? Or am I looking at things incorrectly for one of these options? Thanks!

I run some tests for an iOS app, connecting the iPhone to my mac where the code resides. I notice that it fills the iPhone from system data, until the iPhone is full. I tried everything to remove the system data (I assume some logs from the XCode testing): reset network, restart the iPhone, remove the tested app, etc. Nothing works. I am stuck with having to erase all data on the iPhone and reinstall from scratch, which is very tedious. Any suggestions ? Thanks!