I set up an ec2 instance. In the security group, I opened up SSH 'tcp' port 80 for 0.0.0.0/0 (all open for testing purposes). I associated the instance with a private key. I downloaded the key and passed it while ssh-ing, but the RSA isn't authenticating. Any ideas?
ssh -i mykey.pem root#mydnsinfo.amazonaws.com
The authenticity of host 'mydns.amazonaws.com(IP)' can't be established.
RSA key finger print is FINGERPRINT
Are you sure you want to continue connecting (yes/no)?
Thank you in advance!!!
This is normal. Your SSH complains about the unknown host key. It always does when connecting to the new host for the first time. Just answer yes, connect and try again.
It should not complain for the second time.
The private key that you downloaded is for your 'root' account not for the whole host.
Securely configured EC2 instances will include the server SSH key fingerprint in the console output that you can access over SSL before you try to connect over SSH. Then when you connect over SSH you need to make sure the fingerprint matches the console. You MUST do this to be able to securely connect to public EC2 instances.
Public EC2 instances generate new server SSH key on each boot. This means that unless you do what I described above, you will be faced with unknown host key warning a lot, and if you ignore that warning you will be throwing security out of the door; you just never know where you will be connecting to.
Related
I have a server that I need to connect to sometimes. It has a public IP, but the IP is renewed quite often. To combat that, I have a script that will update a DNS record to map ssh.myurl.com to my new IP.
This setup works, but once the IP changes, I get the error:
WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!
Then I have to delete the key from my client, using ssh-keygen -R ssh.myurl.com, and it works again.
But this seems redundant, as I can't really see how this adds any security. Can I configure this setup so that it always trusts this connection?
The setup is using ProxyJump if that would change anything.
When connecting to a new virtual machine (VM) over SSH for the first time, it is normal to get a message like this:
The authenticity of host '▮▮▮.▮▮▮.▮▮▮.▮▮▮ (▮▮▮.▮▮▮.▮▮▮.▮▮▮)' can't be established.
ECDSA key fingerprint is SHA256:xXxNzzW4OtIxa+O4IDjnj0MmZlrNxHyZtYKw/7rOSfQ.
Are you sure you want to continue connecting (yes/no)?
If I want to be super-careful, how do I check if the fingerprint matches my VM in OpenStack? I can use the Horizon GUI or the openstack CLI, but I can only log into the actual VM with SSH keys, so there's no logging in on the interactive console.
If the VM is using cloud-init, the host keys should be available on the instance "Log" tab on the Horizon Web interface as a part of the console log / booting process output. The printing helper write-ssh-key-fingerprints should run i the cloud-inits final stage.
I am working with win 7 and git bash as well as an amazon EC2 instance. I tried to log into my instance:
$ ssh -i f:mykey.pem ubuntu#ec2-52-10-**-**.us-west-2.compute.amazonaws.com
###########################################################
# 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
71:00:d7:d8:a------------------26.
Please contact your system administrator.
Add correct host key in /m/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /m/.ssh/known_hosts:27
ECDSA host key for ec2-52-10-**-**.us-west-2.compute.amazonaws.com has changed and you have request
ed strict checking.
Host key verification failed.
Logging in like this has worked fine in the past, but this problem started after I rebooted my EC2 instance. How can I get this working again?
edit:
$ ssh -i f:tproxy.pem ubuntu#ec2-52-10-**-**.us-west-2.compute.amazonaws.com
ssh: connect to host ec2-52-10-**-**.us-west-2.compute.amazonaws.com port 22: Bad file number
tried again:
The authenticity of host 'ec2-52-10-**-**.us-west-2.compute.amazonaws.com (52.10.**-**)' can't be
established.
ECDSA key fingerprint is d6:c4:88:-----------fd:65.
Are you sure you want to continue connecting (yes/no)? y
Please type 'yes' or 'no': yes
Warning: Permanently added 'ec2-52-10-**-**.us-west-2.compute.amazonaws.com,52.10.**-**' (ECDSA) t
o the list of known hosts.
Permission denied (publickey).
what should I do now?
The hostname has a new ssh key, so ssh tells you something has changed.
The hint is here:
Offending ECDSA key in /m/.ssh/known_hosts:27
If you're sure the server on the other side is authentic, you should delete line 27 in /m/.ssh/known_hosts.
This error says that something has been changed since your last login to this server and that the server you try to ssh to, might not be the server you think it is.
One thing to be aware of...
When you create an EC2 instance, No fixed IP assigned to this instance.
When you start this instance, it will get (dynamic) IP number and a DNS name which will be based on that IP.
If you shutdown the instance and start it again few hours later, it might get a new IP and a new DNS name.
If you are still trying to access the old DNS name/IP, you are actually trying to access a server that might not belong to you.
This will end with the same error msg as you had.
(It can happen because you pointed a DNS entry to the old IP, or you are using scripts that try to access the old DNS name/IP, or you just repeating the ssh command from your history...)
If this is the case, the solution is to use Elastic IP.
You can assign Elastic IP to your server, and this will force it to keep its IP address between reboots.
Elastic IP is free while your (attached) server is up.
But it will cost you some minor fees when the attached server is down.
This is done to make sure you are not "reserving" IP while not using/need it
In BeanStalk environment, the issue is that it refers to the key from known_hosts for the respective IP. But it has changed. So using the same key would not work.
Removing the key for the IP from ~/.ssh/known_hosts and then connecting by ssh would work.
(Basically, when the entry is not there in ~/.ssh/known_hosts it will create a new one, and thus resolve the conflict)
Type the following command to set the permissions. Replace ~/mykeypair.pem with the location and file name of your key pair private key file.
chmod 400 ~/mykeypair.pem
In your case mykeypair.pem is tproxy.pem
I was facing the same issue and after making pem file private it was fixed.
Here is some more information on SSH Key Permissions
Sorry but I am a newbie... I have checked other questions but nothing has worked and I am not great with SSH.
Followed the steps to connect to EC2 with SSH in Eclipse. Worked like a charm. Then I terminated the working server and started a new instance.
Now I can't connect and receive
RSEG1066 "Failed to connect sshd on server name" Auth failed
Also Port 22 is open ->
Port 22 (SSH) Source: 0.0.0.0/0
My SSH connection references the new hostname and I have applied my .pem file via rsa. Any thoughts? What else should I check?
Thank you.
Seems many people are having this problem with AWS when terminating an instance and launching a new instance. Here is what I did to solve the problem for me.
Terminated instance
Deleted key pair from AWS console
Deleted key pair from client
Launched a new instance
When prompted, used a different name for my key pair (.pem) file
Choose the default security group
Added SSH / Port 22 inbound access to the security group
Connected (with user *ubuntu* since I am using an ubunutu server)
And if using Eclipse RSE like the tutorial link in the original question, be sure to restart Eclipse before connecting.
Hello! I have problem with connecting to remote host. I forgot ssh password but I have Fingerprint of the SSH Key. Is it possible to connect with using just fingerprint?
No. The fingerprint of the machine is just used to verify you're connecting the machine your think you're connecting to. It is public information used to avoid Man in the Middle Attacks (MITM) on your SSH session.