Host Key Error on incline/icsf Nodes
We have now taken the old 64GB & 256GB nodes out of service. These were accessed via the addresses
incline.itservices.manchester.ac.uk icsf.itservices.manchester.ac.uk incline256.itservices.manchester.ac.uk icsf256.itservices.manchester.ac.uk
Those addresses are still valid but they will now log you into one of the incline2000 nodes. This may cause you to see an error when logging in. See below on how to fix it:
When logging in to one of the above addresses
ssh -X username@incline256.itservices.manchester.ac.uk
#
# (optional - the error may occur below with or without -X)
you may receive one or both the following errors about host identification:
PLEASE NOTE: incline.itservices.manchester.ac.uk – IP is 10.99.203.43 (change if appropriate)
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
The RSA host key for incline256.itservices.manchester.ac.uk has changed,
and the key for the corresponding IP address 10.99.203.70
has a different value. This could either mean that
DNS SPOOFING is happening or the IP address for the host
and its host key have changed at the same time.
Offending key for IP in /home/username/.ssh/known_hosts:70
remove with: ssh-keygen -f "/home/username/.ssh/known_hosts" -R 10.99.203.70
#
#
# If you see this message, follow the instructions: run
#
# ssh-keygen -f "/home/username/.ssh/known_hosts" -R 10.99.203.70
#
# (use the file path and username reported in your message!)
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
xx:xx:xx:xx:xx......:xx.
Please contact your system administrator.
Add correct host key in /home/username/.ssh/known_hosts to get rid of this message.
Offending RSA key in /home/username/.ssh/known_hosts:4
remove with: ssh-keygen -f "/home/username/.ssh/known_hosts" -R incline256.itservices.manchester.ac.uk
RSA host key for incline256.itservices.manchester.ac.uk has changed and you have requested strict checking.
Host key verification failed.
#
#
# If you see this message, follow the instructions: run
#
# ssh-keygen -f "/home/username/.ssh/known_hosts" -R incline256.itservices.manchester.ac.uk
#
# (use the file path and username reported in your message!)
This occurs because incline256.itservices.manchester.ac.uk now defaults to using the incline2000 nodes which use a different host key.
Solutions
The easiest way to fix this if logging in from Linux (e.g., our X2GO desktop), or from MacOSX or in MobaXterm is to run the following command(s) in your terminal window (note: you will not be logged in to the iCSF at this point):
PLEASE NOTE: incline.itservices.manchester.ac.uk – IP is 10.99.203.43 (change if appropriate)
ssh-keygen -f "/home/username/.ssh/known_hosts" -R 10.99.203.70
ssh-keygen -f "/home/username/.ssh/known_hosts" -R incline256.itservices.manchester.ac.uk
#
#
#
# Use the correct path and username reported in your error!
You should then log in using ssh:
ssh -X username@incline256.itservices.manchester.ac.uk
you will be asked to accept the new key:
The authenticity of host 'incline256.itservices.manchester.ac.uk (10.99.203.70)' can't be established.
ECDSA key fingerprint is xx:xx:xx:xx:xx......:xx.
Are you sure you want to continue connecting (yes/no)? yes
#
# Type yes and press Enter
It is safe to do so – answer yes at the prompt. You will then be logged in to one of the 2TB compute nodes.