Network connectivity issues on macOS client

[anthonypants]

I don't know at what point this issue started exhibiting itself, but for the longest time I thought it was some combination of Little Snitch rules and the iCloud Private Relay. But I uninstalled Little Snitch and disabled the Private Relay feature, and this issue didn't go away. So I reinstalled Little Snitch and told it to block 172.0.0.0/8 addresses, and that resolved my issue.

You see, I created a different thread about this a month ago, but my Windows 10 server has several virtual network adapters, and Synergy recognizes all of them, for some reason (but no IPv6...?). And while my macOS client is connected to the actual Synergy server, using the 10.0.0.0/8 network addresses my computers are actually using, it also receives these other 172 addresses, for some reason. And the Synergy client tries to connect to them. For some reason. And the logs report that the Synergy client is constantly, like, several dozen times a second, reporting errors like ETIMEDOUT, or EADDRNOTAVAIL, and probably some other ones I can't remember, trying to connect to these bogus addresses. And I think macOS doesn't like that? There's probably some way to monitor like, ephemeral port exhaustion, or maybe I'm hitting a limit on open TCP connections, or the issue could be with some other device on my network, but I really don't care to dig any deeper than this.

[MacStephen]

I had a similar issue with the ETIMEOUT, EADDRNOTAVAIL floods. 

 

I considered posting here, but 1.) Devs don't respond/ack 2.) I didn't feel like getting all the logging information to really understand what was going on.

In my case, Synergy 3 Beta would cause connectivity issues on my network for other clients, to the point where I had assumed my ISP was having regular outages. This miraculously fixed itself each time once I killed the Synergy Client on all machines. This was repeatable. behavior.