Ssh connection from IQmol on Mac

I am not a Mac user, but am trying to support a student who is trying to use ssh to run Q-chem on a remote machine using IQmol. She can connect via ssh through the terminal directly, but when trying to submit a job though IQmol receives the error: “Failed to connect to server XXX: SSH host key not found in”. The server name and user name are correct, and we have tried with and without defining locations for ssh key files (and the same configuration works fine for me from a PC). The default Q-chem server also works for her with no problems. Has anyone else encountered this? Are there settings on the Mac that need to be changed?

It looks like this is actually an issue with the newest release of IQmol. I downloaded 2.15 and now am having the same issue on my PC (2.14 was working fine).

As of 2.15 IQmol checks the known_hosts file to check the host key is correct to help prevent man-in-the-middle attacks. Assuming you have specified the correct location for the known_hosts file in the server setup, it sounds like the host key is not actually in the file. Are you able to confirm this?

Thank you for the reply, I did specify the known_hosts file, and it looks like the computer I’m trying to connect to is there. I just now tried it again and it seems to be working (I didn’t change anything in my configuration settings). I guess it’s possible there was some issue with the university network that was creating the issue a couple days ago, although the problem lasted a few days.

One other thing to watch is if you make changes to a server configuration after attempting a connection which fails, sometimes the changes do not take effect until IQmol is restarted.

I encountered a similar problem ~1 month ago and it appears to be only a sporadic problem. (Technical issue on Q-Chem side, I think.) Workaround suggested by Q-Chem staff at the time was to go into Calculation --> Edit Servers, click on the Q-Chem server, and change the connection type from HTTPS (default value on Mac) to HTTP.