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1217 Discussions

host key change

User01
New Contributor II
3,837 Views

Did the host key change for DevCloud login nodes on June 22, 2022?

 

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ 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 ED25519 key sent by the remote host is
SHA256:/Dlip01tdMyRmhMDc870Z4Uk7AancwwoTnbb0EZajK0.
Please contact your system administrator.

 

0 Kudos
1 Solution
AlekhyaV_Intel
Moderator
3,493 Views

Hi All,

 

Sincere apologies for making you all wait. @User01 @risan-raja @khush @Oluwatosin @ral 

 

You can try the below steps to re-connect to devcloud again.

1) Download the new key from this link: https://devcloud.intel.com/oneapi/documentation/connect-with-ssh-linux-macos/

2) Move/Copy this file to ~/.ssh folder & rename it to "devcloud-access-key-xxxxx.txt"

3) Give permissions to the file/folder as below:

chmod 600 ~/.ssh/devcloud-access-key-xxxxx.txt
chmod 600 ~/.ssh/config 

(Ignore this step if you're connecting through Mobaxterm. This step is required only for Cygwin.

 

If this resolves your issue, please accept this as a solution as it might help others with the similar issue. Thanks in advance. Please let us know if this issue still persists.

 

Regards,

Alekhya

 

View solution in original post

38 Replies
User01
New Contributor II
2,725 Views

It looks like DevCloud is down again. I am unable to connect after accepting the new host key. In addition, the site at https://devcloud.intel.com/oneapi/documentation/connect-with-ssh-windows-cygwin/ gives:

 

"Internal Server Error
The server encountered an internal error and was unable to complete your request. Either the server is overloaded or there is an error in the application."

 

ral
Novice
2,708 Views

I am having the same issue, keep getting there following error
guest@ssh.devcloud.intel.com: Permission denied (publickey).
kex_exchange_identification: Connection closed by remote host

Oluwatosin
New Contributor I
2,697 Views

I am having this exact issue right now...

Oluwatosin
New Contributor I
2,686 Views

@User01 I was able to solve the problem ( I am using Windows Subsytem for Linux (Ubuntu 20.04.4 LTS) for connecting to the devcloud). 

 

Below are the steps I took: (I hope you find it useful)

 

Action to replicate warning: connect to devcloud

username@desktop $ ssh devcloud

```
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ 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 ECDSA key sent by the remote host is
SHA256:****************************************************************
Please contact your system administrator.
Add correct host key in /home/user/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /home/user/.ssh/known_hosts:1
remove with:
ssh-keygen -f "/home/user/.ssh/known_hosts" -R "ssh.devcloud.intel.com"
ECDSA host key for ssh.devcloud.intel.com has changed and you have requested strict checking.
Host key verification failed.
kex_exchange_identification: Connection closed by remote host
```

 

Steps to remove warning:

 

Step 1: Remove offending ECDSA key from known_hosts

You can do remove by 

username@desktop $ cd .ssh

username@desktop $ vi known_hosts

>> Then delete first line in known_hosts file (since offending key is known_hosts: 1)

or 

username@desktop $ ssh-keygen -f "/home/user/.ssh/known_hosts" -R "ssh.devcloud.intel.com"

 

Step 2: After removing offending key, known_hosts should be updated

username@desktop $ ssh-keygen -f "/home/user/.ssh/known_hosts" -R "ssh.devcloud.intel.com"

# Host ssh.devcloud.intel.com found: line 1
/home/user/.ssh/known_hosts updated.
Original contents retained as /home/user/.ssh/known_hosts.old

 

Step 3: connect to devcloud again

username@desktop $ ssh devcloud

>> enter yes to continue connecting

The authenticity of host 'ssh.devcloud.intel.com (12.229.61.118)' can't be established.
ECDSA key fingerprint is SHA256:fdh1CzIao2MCh6YQ3uP7ZZyZF0XqieU7OY6DjcDctq4.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added 'ssh.devcloud.intel.com' (ECDSA) to the list of known hosts.
Warning: the ECDSA host key for 'ssh.devcloud.intel.com' differs from the key for the IP address '12.229.61.118'
Offending key for IP in /home/oluwatosin/.ssh/known_hosts:1
Are you sure you want to continue connecting (yes/no)? yes

###############################################################################
#
# Welcome to the Intel DevCloud for oneAPI Projects!
#.........
###############################################################################

u*****@login-2:~$

 

NOTE: There is still a warning above:

Warning: the ECDSA host key for 'ssh.devcloud.intel.com' differs from the key for the IP address '12.229.61.118'

 

So if you try to connect to the devcloud again, you should get this warning and you will have to enter yes before you are directed to your devcloud login node:

username@desktop $ ssh devcloud


Warning: the ECDSA host key for 'ssh.devcloud.intel.com' differs from the key for the IP address '12.229.61.118'
Offending key for IP in /home/user/.ssh/known_hosts:1
Matching host key in /home/oluwatosin/.ssh/known_hosts:6
Are you sure you want to continue connecting (yes/no)? yes

###############################################################################
#
# Welcome to the Intel DevCloud for oneAPI Projects!
#...........
###############################################################################

u*****@login-2:~$

 

Step 4: remove offending key for IP in /home/user/.ssh/known_hosts:1 indicated in the warning above

username@desktop $ cd .ssh

username@desktop $ vi known_hosts

>> Then delete first line in known_hosts file (since offending key for IP is known_hosts: 1)

 

Step 5: Connect to the devcloud again

username@desktop $ ssh devcloud

(The warning below will be prompted)

Warning: Permanently added the ECDSA host key for IP address '12.229.61.118' to the list of known hosts.

###############################################################################
#
# Welcome to the Intel DevCloud for oneAPI Projects!
#...........
###############################################################################

u*****@login-2:~$

 

You are all set to ssh devcloud again without any disturbances.

 

Step 6: connect to devcloud

username@desktop $ ssh devcloud

###############################################################################
#
# Welcome to the Intel DevCloud for oneAPI Projects!
#...........
###############################################################################

u*****@login-2:~$

 

I hope this helps!

 

Regards and Thanks,

Oluwatosin.

gamersensual14
New Contributor I
2,296 Views

This worked!! Thank you so much Oluwatosin!

Oluwatosin
New Contributor I
2,272 Views
ral
Novice
2,679 Views

This solution did not work for me, I still get

 

guest@ssh.devcloud.intel.com: Permission denied (publickey).
kex_exchange_identification: Connection closed by remote host
Connection closed by UNKNOWN port 65535

 

 

Oluwatosin
New Contributor I
2,673 Views

@ral what terminal (linux, cygwin, e.t.c. ) are using to connect to devcloud ?

ral
Novice
2,665 Views
Oluwatosin
New Contributor I
2,659 Views

Okay, I have git bash, and I am going to try to add devcloud to my git bash and try to connect from there, to see if I get the same issue.

 

I will get back to you.

Oluwatosin
New Contributor I
2,650 Views

 

@ral I have just tried to add devcloud to my list of known hosts using git bash for windows and I am able to connect to the devcloud with ssh devcloud.

Could you try re-adding devcloud to the list of known hosts by following this commands ?

 

open git bash

 

>> make a temporary directory to store your devcloud details

user@desktop MINGW64 ~ mkdir key

>> go to .ssh directory where you have your devcloud details

user@desktop MINGW64 ~ cd .ssh

>> copy config and access key files to temporary key directory

user@desktop MINGW64 ~/.ssh cp config devcloud-access-key-*****.txt ~/key

>> check that config and access key files are in the key directory

user@desktop MINGW64 ~/.ssh cd ~

user@desktop MINGW64 ~ cd key

user@desktop MINGW64 ~/key ls

>> remove config and access key files from .ssh directory

user@desktop MINGW64 ~/key cd ~/.ssh

user@desktop MINGW64 ~/.ssh rm -i config devcloud-access-key*****.txt

 

(you may restart git bash at this point; exit and open again)

 

>> go to temporary key directory

user@desktop MINGW64 ~ cd key

>> copy config and access key files to .ssh directory

user@desktop MINGW64 ~/key cp config devcloud-access-key*****.txt ~/.ssh

>> go to home directory 

user@desktop MINGW64 ~/key cd ~/

>> remove temporary key directory

user@desktop MINGW64 ~ rm -r key

>> connect to devcloud

user@desktop MINGW64 ~ ssh devcloud

>> enter yes to add ssh.devcloud.intel.com to list of known hosts

The authenticity of host 'ssh.devcloud.intel.com (12.229.61.118)' can't be established.
ED***** key fingerprint is SHA256:**********************************************************
This key is not known by any other names
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added 'ssh.devcloud.intel.com' (ED*****) to the list of known hosts.
The authenticity of host 'devcloud (<no hostip for proxy command>)' can't be established.
ED***** key fingerprint is SHA256:************************************************************
This key is not known by any other names
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added 'devcloud' (ED*****) to the list of known hosts.

 

see if this fixes it.

 

Regards and Thanks,

Oluwatosin.

Oluwatosin
New Contributor I
2,642 Views

@ral if you still experience the issue, you may want to download the "setup-devcloud-access-*****.txt" file again and try connecting DevCloud.

Oluwatosin
New Contributor I
2,638 Views

@User01 and @ral have you been able to solve the problem ?

User01
New Contributor II
2,561 Views

@Oluwatosin - Thank you for your help; however, the original post was not a question about how to manage client-side SSH host keys in the known_hosts file. I was attempting to get a response from Intel DevCloud administrators with confirmation that they changed the server host key and verified that I was not experiencing a man-in-the-middle attack. Usually, administrators of a shared resource will provide a notification when those keys are changed, and I have not seen any information from Intel. Simply changing the key value in known_hosts as a work-around to the alert is a bad practice as it circumvents the purpose of the check and notification. Your instructions may be beneficial to users once it has been confirmed that the host key has legitimately changed. But those steps should not be followed until the change is confirmed.

I also see that loading https://devcloud.intel.com/oneapi/documentation/connect-with-ssh-windows-cygwin/ gives a "500 Internal Server Error." That URL usually includes user-specific credentials. The failure for that page to load indicates a service issue on Intel's side.

As of this post, the Intel DevCloud remains inaccessible to me, and the cause is something on Intel's side. See @AlekhyaV_Intel 's post for confirmation.

Oluwatosin
New Contributor I
2,531 Views

@User01 Alright. 

I also experienced the 500 Internal Server Error yesterday and I am still experiencing it today. I discovered the error only after I tried to fix the devcloud connection issue.

 

Yes, you are right to say the issue is with Intel; and I also read @AlekhyaV_Intel response earlier today.

 

Hopefully, Intel is able to fix the affected services soon.

AlekhyaV_Intel
Moderator
2,603 Views

Hi,


Thank you for posting in Intel Communities. Sorry for the inconvenience caused. It is a known issue and we are looking into it. We will get back to you with an update soon.


Thanks & Regards,

Alekhya


risan-raja
Novice
2,585 Views

Hi

I am facing this issue as well

 

khush
Beginner
2,517 Views

khush_0-1656022780745.png

I am facing the the issues. I have changed the key-gen too. 

risan-raja
Novice
2,504 Views

My issue is similar to @khush .

I have redownloaded the key. Tried clearing .ssh directory in the home folder.

 - I have also tried generating new ssh keypairs by running

ssh-keygen -t rsa
chmod a+x setup-XXXXXXX.txt
bash setup-XXXXXX.txt
chmod 600 ~/.ssh/config
chmod 600 ~/.ssh/devcloud-XXXXXX.txt
# Now I retry
ssh devcloud

risanraja_0-1656039116724.png

The above is the output I recieved.

 

 

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