After the recent update of High Sierra, when I try to connect to another device via ssh, i keep getting the following error:
ssh_dispatch_run_fatal: Connection to <IP ADDRESS OF REMOTE END> port 22: Invalid key length
MacBook Pro (Retina, 13-inch,Early 2015), macOS High Sierra (10.13.2)
Looks like this is due to the OpenSSH version in MacOS getting upgraded to 7.6. The release notes (available here: https://www.openssh.com/releasenotes.html) list "Refuse RSA keys <1024 bits in length and improve reporting for keys that do not meet this requirement." as a 'potentially-incompatible change'.
So far, the only 'work-around' I've found is to re-generate the RSA key, with a size of 1024 bits or larger, on the server you're connecting to.
Looks like this is due to the OpenSSH version in MacOS getting upgraded to 7.6. The release notes (available here: https://www.openssh.com/releasenotes.html) list "Refuse RSA keys <1024 bits in length and improve reporting for keys that do not meet this requirement." as a 'potentially-incompatible change'.
So far, the only 'work-around' I've found is to re-generate the RSA key, with a size of 1024 bits or larger, on the server you're connecting to.
I have this same problem, only I didn't do an update over the weekend. (Unless Logic Pro X update included an update to SSH.) I first noticed this problem today (Dec 18), but my last OS update was on Dec 11 and Dec 7.
Thank you very much josephizf. Silly me for not figuring that out myself.
On a side note, just in case anyone trying to connect to cisco devices (as i did in this case), just don't forget to zeroize rsa after you have re-generated the RSA key on the device (with size greater than 1024 bits).
Thanks again 🙂
ssh_dispatch_run_fatal Invalid key length
