ssh tunnel not working after Sequoia update

Same here: I have not been able to maintain a stable SSH connection to a remote office over a Wireguard VPN after upgrading to Sequoia. The connection drops after about 30 secs saying the connection is corrupted.

Turning off LuLu solved the issue.

Thank you!!!

I have the same problem on a MacBook Pro with SSH both on Terminal (slightly less common) and iTerm2 with Sequoia. This isn't SSH tunnel specific for me, just SSH generally. Interestingly, my Macbook Air with same version doesn't have this issue. The only difference was the Pro has Little Snitch as well.

Downloading a 5GB file using curl within terminal/iTerm2 over HTTPS also causes this. One stopped 673MB, another 2.2GB, so it may take some time to trigger. This shows it's not SSH related as such.

Apple was bouncing me around different departments not knowing who I need to speak to having an MDM profile on here (but it doesn't seem related anyway). Not experimented with Wireguard yet.

KEY POINTS:

• With Little Snitch firewall installed (even when not filtering) *and* MacOS Firewall enabled, the problem happens
• Disabling MacOS firewall fixes the issue
• Uninstalling Little Snitch fixes the issue.

Update:

The problems (SSH and Microsoft Remote Connection) for me disappeared when I disabled the installed / used LuLu Firewall.

Same for me. ssh started working as expected after disabling the built-in firewall.

I have the same problem since macOS 15.0 install.

SSH connects and after some seconds I was disconnected with the error message:

ssh_dispatch_run_fatal: Connection to xx.xx.xx.xx port 22: message authentication code incorrect

I also experienced a comparable problem with a Microsoft Remote Connection to a (local) Windows System.

The connection was established and after a few seconds was disconnected because of "data encryption error".

LittleSnitch blogged about this:

https://www.obdev.at/blog/should-i-upgrade-to-macos-sequoia-now/