Troubleshoot Login

Troubleshoot Login

If you are having trouble logging in, please check the following:

  1. Check the status page to make sure that your cluster is online: System Status
  2. Verify that you are attempting to ssh to the correct hostname. Please see the list of login nodes.
  3. If you get an error like "could not resolve hostname" make sure that you are using the Yale DNS servers (130.132.1.9,10,11). External DNS servers do not list our clusters.
  4. Verify that your ssh keys are setup correctly. You may use the ssh key uploader to check the keys you have uploaded and to re-install your public key if needed. After uploading, please wait 30 minutes for your key to be installed
  5. If you are using Ruddle or Farnam, they require Duo MFA on your smartphone.
  6. Make sure you are accessing the cluster from either Yale's campus networks (ethernet or YaleSecure for wireless) or Yale's VPN if you are off-campus.

If you are still unable to login, it is possible that the permissions to your home directory were inadvertently modified. The home directory should only be write-able by your NetID.

If all of the above check out ok, please contact us and we will investigate further.


"REMOTE HOST IDENTIFICATION HAS CHANGED!" Warning

If you are seeing the following error:

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
....
Offending key in /home/user/.ssh/known_hosts:34
...

This error means that the host keys on the cluster have changed. This may be the result of system upgrades on the cluster. It could also mean someone is trying to intercept your ssh session. Please contact us if you receive this error.

If the host keys have indeed changed on the server you are connecting to, you can edit ~/.ssh/known_hosts and remove the offending line. In the example above, line 34 in ~/.ssh/known_hosts would have to be deleted before you re-connect.