Due to security requirements, we are changing the host identification keys for our FIS systems, including systems named fis, fastfis, and tapefis (in the CZ and SCF) and rzfis, rzfastfis, rztapefis (in the RZ).

Impact

Users connecting to these systems from their local machines (including non-LC computers and iSRD desktops) may see an error message starting with "WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED" (full text in the screen shot below). The attempt to connect to FIS system will then be denied.

For Hopper users, connections to FIS systems will not be successful and users may or may not be prompted for username and password. The bottom bar of the main Hopper window will show "ERROR -- CLICK HERE FOR DETAILS" and will lead users to the error message displayed in the below screen shot.

Hopper error message indicating remote host identification has changed.

This error message is due to caching of the FIS system identification keys on your local system, specifically in the ~/.ssh/known_hosts file.

Solution

Users can do any of the following:

  1. Download the known_hosts2 file. Users can download this LC-provided file which specifies the current RSA host keys for all LC clusters. Values in the known_hosts2 file will override the erroneous entries in known_hosts. 

  2. Remove the bad entries from the ~/.ssh/known_hosts file. The offending entry is indicated in the error message (for example line 19 as indicated by the :19 in the error message above).

  3. Remove the entire ~/.ssh/known_hosts file. This can be accomplished quickly with the command:

    mv ~/.ssh/known_hosts ~/.ssh/known_hosts.old

    When choosing this solution, users may be prompted by confirm future to connections to LC clusters on the command line.