Fixing SSH after upgrading to macOS 10.13.2 =========================================== By George Mandis https://george.mand.is/2017/12/fixing-ssh-after-upgrading-to-macos-10132 Thursday, December 14th 2017 I recently upgraded to macOS 10.13.2 and tried to SSH into a project I’ve been working on to check on the logs. The error read: `Unable to negotiate with XX.XX.XXX.XX port 22: no matching cipher found. Their offer: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se` I’m not precisely sure what changed, but thankfully the fix turned out to be relatively simple. In your `/etc/ssh/ssh_config` file you should see many lines that have been commented out. Find the one that looks like this and uncomment it: `Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc` It should work as it did before. Apple’s had a slew of rough updates lately, between the strange bug where you couldn’t type the letter “i” on iOS and the inexcusable [root login bug](https://daringfireball.net/2017/11/high_sierra_root_login_two_weeks_ago). Upgrading to 10.13 a couple weeks ago froze my computer and forced me to restart the computer in recovery mode, which I’ve pretty much never had to do. Hopefully this isn’t a trend that continues.