Yep, I concur: this explains a bizarre behavior I’ve noted in my Mac laptops for ages now. I have a tendency to just suspend them without rebooting for ages, especially the work one that doesn’t leave my office as frequently. Periodically, I’d come in to find the system bizarrely frozen just as they describe: TCP stack blocked up, but everything else on it behaving normally. (Well, mostly: some apps would block starting and bounce eternally, but I suspect that’s because they’re trying to make a network call while starting up and it’s blocking.) The only fix was a reboot.

It’s not a disaster, but very annoying. At least now I can just schedule a reboot every 30 days at minimum to keep things running.

GP said that suspending without rebooting prevents the issue.

My uptime resets only when forced by an OS upgrade and I have never experienced this issue. This is consistent with the sleep-heals-the-stack theory.

I experienced the exact same issue. Now that I know, I know what to do.

I would not be surprised if people on HN were more likely to hit this issue than Apple's average users. We're a weird bunch ;)

Can confirm at least on of us (me) is weird.