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Fix SSH host key error for Oracle SQL on linux.cci.drexel.edu

Introduction

Mac Terminal or Putty or another SSH client or command-line SSH or SCP should be able to connect as normal to Tux. You will need to accept a new host key when connecting. If you have trouble accepting it the RSA key, or get an error about a key or RSA key, try the following.

Windows

  1. In cmd.exe or Powershell, type in:
    cd C:\Users\username\.ssh
    Where username is your username on the computer you are using.
    You can also click folders in File Explorer to get to above.
  2. Open known_hosts file.
  3. Inside the known_hosts file, delete all lines that say
    linux.ischool.drexel.edu,129.25.203.45 ssh-rsa
    or
    linux.cci.drexel.edu,129.25.203.45 ssh-rsa
    or
    linux.cis.drexel.edu,129.25.203.45 ssh-rsa
    Delete the lines if they have different IP addresses as well.
    It might be all on *one* line, separated by commas.
    You can just delete the entire line.
  4. Once you remove those lines, and save the file, you will be able to connect.
  5. Say "Yes" to accept the new host key when prompted.

Mac

  1. Open Terminal, and type in:
    cd /Users/username/.ssh
    where username is your account name on your Mac.

    If you navigate through Finder, click "View" > "Show Path" par,
    look for Macintosh HD or the like at bottom of Finder window, and double-click it.
    To go to the .ssh folder, once you are in /Users/username/ ,
    press "Command" + "Shift" + . key which will show the hidden folders on your Mac
  2. Open the file "known_hosts" in /Users/username/.ssh using TextEdit app.
  3. Inside the known_hosts file, delete all lines that say
    linux.ischool.drexel.edu,129.25.203.45 ssh-rsa
    or
    linux.cci.drexel.edu,129.25.203.45 ssh-rsa
    or
    linux.cis.drexel.edu,129.25.203.45 ssh-rsa
    Delete the lines if they have different IP addresses as well.
    It might be all on *one* line, separated by commas.
    You can just delete the entire line.
  4. Save the file and try connecting again.
  5. Once you remove those lines, and save the file, you will be able to connect.
  6. Say "Yes" to accept the new host key when prompted.

Linux

  1. Run the command ssh-keygen -f "/path/to/.ssh/known_hosts" -R "linux.ischool.drexel.edu" 
    • The path is often ~/.ssh/known_hosts, but may change depending on your system.
    • You may also need to remove "linux.cci.drexel.edu" or "linux.cis.drexel.edu".
  2. Connect to linux.cci.drexel.edu
  3. Accept the new Host Key.
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