Problem
Does the 'user#host' of the id_rsa.pub need to match with the actual machine username - host and then with the username in Gitlab?
Example:
Gitlab username name: #john.doe
Ubuntu Machine hostname command hostname: JOHNDOE
Ubuntu username: mark
Username in the id_rsa.pub: ...fsdfsdfsdfsd mark#JOHNDOE
So as you can see, my user in Ubuntu is mark and the ssh rsa key generated has a mark#JOHNDOE as last domain. But should it be john.doe#JOHNDOE instead (both in Ubuntu user and in the ssh pub key)?
And let's say that for some reason I cannot change the user in my Ubuntu machine.
I honestly think the answer is no and the issue is on my user in Gitlab that has some missing permissions or some network related problem, and I'm just paranoid but just to make sure that is not related with the ssh keys.
I think the ssh key just need to match the one in Gitlab and the username in the key has nothing to do (because actually, you can change it with command -C "john.doe#JOHNDOE" which is a Comment and anyway it still gives me errors. But again I have the doubt is ALSO the username of the Ubuntu must be john.doe
Command run / Troubleshot
OS: Ubuntu 18.04.6 LTS on Windows 10 x86_64 (WSL)
I need to connect via VPN (all other https services works via Browser so it should be fine)
Creating ssh
ssh-keygen -t rsa -b 2048
Add SSH
cat ~/.ssh/id_rsa.pub
# Then copy the key to gitlba key - etc..
Also try do
eval $(ssh-agent -s)
ssh-add -D
ssh-add ~/.ssh/id_rsa.pub
Error
Do a git clone
Please make sure you have the correct access rights and the repository exists.
Connecting
ssh -T git#gitlab.example.com
banner exchange: Connection to [here the IP but removed] port 22: Connection timed out
Ok so the problem is the VPN software that I used.
As #Raya pointed out the answer to my question is:
No, the user in the ssh public key does not matter
As soon as I changed the VPN it start to work therefore the problem was Network related
Will auto-post the answer and mark as accepted, but won't close the question so if anyone has better information can add it.
SSH has been working fine for the last few weeks since I got my new PC. I've had no problems but today I started getting:
ssh: connect to host github.com port 22: resource temporarily unavailable
I did some googling and found that there is a common issue with WSL which sometimes causes this, but I'm unable to SSH from my bash shell, or from cmd/powershell.
This is the part that confuses me, if I do: ssh -T git#192.30.253.113 I am prompted for the password to my key, it successfully authenticates and responds with "Hi alexmk92! You've successfully authenticated".
Great, that at least proves that my firewall isn't blocking SSH on port 22. But why does git#github.com throw the resource failed error? My initial thought is that this could be a DNS problem.
So I tried to configure my network adapter to use Google's DNS server (8.8.8.8 and 8.8.4.4) I even configured the IPV6 DNS servers just in case. Following this I did an ipconfig /flushdns, attempted to connect via git#github.com again and BAM the same result, however git#192.30.253.113 still works.
I'm guessing another potential cause is that github.com is behind a load balancer and one of the IP's on the cluster could be black-listed somewhere on my machine? I'm just pulling guesses out of thin air now, any help would be greatly appreciated, this is driving me insane.
After some further Googling it turned out that my machine did not have a hosts entry for github.com and it was unable to automatically resolve it.
In Windows Subsystem for Linux I created a ssh config file
touch ~/.ssh/config
(for some reason the base distro of Ubuntu 18.04 on the windows marketplace didn't have one) I then had to make sure the file permissions were correct:
chmod 755 ~/.ssh/config
Once the file was created, I edited it with
sudo nano ~/.ssh/config
and added github.com as a Host.
Host github.com
Hostname ssh.github.com
Port 22
Upon saving, I ran
sudo /etc/init.d/ssh restart
and attempted
ssh -T git#github.com
Everything now seems to be working.
In my case my ISP did not allow ssh, so it was not working from cmd and wsl both. Got around it using vpn
To have successful SSH connection to Github, SSH key has to be import into Github
Open Git bash or Terminal
Run the command ssh-keygen
Choose all default option
A private and a public key gets generated in the folder * < user_home>/.ssh/*
Login to Github.com
Navigate to account settings
Choose item "SSH and GPG Keys" from the side navigation bar
click added new SSh key
Copy and save public key content from * < user_home>/.ssh/id_rsa.pub *
I can connect using these credentials through ftp but not through ssh.
Timothy#ement MINGW64 ~
$ ssh timothy#mywebsite.com
ssh: connect to host mywebsite.com port 22: Connection timed out
I'm sure this question has been asked a million times before. Does it have anything to do with ssh keys?
I'm using siteground and in the ssh/shell access area i've added this:
t r timothy#mywebsite.com KtV/T4QvP4K9n7Zki9n+ZWp6 0.0.0.0/0 - ALL Remove Key | Add IP | Private Key
any help would be appreciated. Thank you.
Does it have anything to do with ssh keys?
Yes: see the official SiteGround documentation How to use SSH.
you need to enable ssh access and register your public ssh key.
then you can use ssh (provided in your <path-to-git>/usr/bin) in order to access
ssh -p18765 <user>#yourdomain
SiteGround chooses to run its sshd on port 18765, not the default 22.
The siteground tutorials are junk, two out of the three chat support staff I spoke with just referred me to the tutorials when I was attempting to make a connection to my siteground server over ssh.
These are the steps that finally worked:
From the cPanel Advanced section select SSH/Shell Access
Generate a new key using their utility (make note of the password you used for later use).
*** They have a tutorial that should allow you to create a private key on linux then upload the public key to their site. That is "not recommended" and I was unable to get that to work.
Once you have their key listed in the current keys table click the Private Key link
Copy the Private Key to a file in your local .ssh directory (make sure the mask is 0600)
run the following command:
ssh-add
enter the passphrase you used when generating the key using their utility
If you get a response "Identity added: ..." you are all set
you should now be able to use the command:
ssh # -p18765
It doesn't look like they have X11 forwarding enabled though so if you use ssh -X you will get:
X11 forwarding request failed on channel 0
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I've reinstalled my server and I am getting these messages:
[user#hostname ~]$ ssh root#pong
###########################################################
# 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
6e:45:f9:a8:af:38:3d:a1:a5:c7:76:1d:02:f8:77:00.
Please contact your system administrator.
Add correct host key in /home/hostname /.ssh/known_hosts to get rid of this message.
Offending RSA key in /var/lib/sss/pubconf/known_hosts:4
RSA host key for pong has changed and you have requested strict checking.
Host key verification failed.
I have tried various solutions that I found on the Internet. My known_hosts file (normally in ~/.ssh/known_hosts) is in /var/lib/sss/pubconf/known_hosts. I've tried to edit it, but it remains in one state. I have installed ipa-client and have Fedora 19. How do I resolve this warning?
All the answers answered so far work only if you do not have Freeipa installed.
The right answer for freeipa in comments below from adrin is here.
Here is the simplest solution:
ssh-keygen -R <host>
For example,
ssh-keygen -R 192.168.3.10
From the ssh-keygen man page:
-R hostname Removes all keys belonging to hostname from a known_hosts file. This option is useful to delete hashed hosts (see the -H option above).
Use
ssh-keygen -R [hostname]
Example with an ip address/hostname would be:
ssh-keygen -R 168.9.9.2
This will update the offending of your host from the known_hosts. You can also provide the path of the known_hosts with -f flag.
I had this same error occur after I recreated a Digital Ocean Ubuntu image. I used the following command with my server IP in place of [IP_ADDRESS]
ssh-keygen -R [IP_ADDRESS]
The sledgehammer is to remove every known host in one fell swoop:
rm ~/.ssh/known_hosts
On Monterey
sudo rm /var/root/.ssh/known_hosts
I come up against this as we use small subnets of short-lived servers from a jump box, and frequently have internal IP address reuse of servers that share the same ssh key.
When you reinstall the server its identity changes, and you'll start to get this message. Ssh has no way of knowing whether you've changed the server it connects to, or a server-in-the-middle has been added to your network to sniff on all your communications - so it brings this to your attention.
Simply remove the key from known_hosts by deleting the relevant entry:
sed '4d' -i /var/lib/sss/pubconf/known_hosts
The 4d is on the account of Offending RSA ...known_hosts:4
The problem is that you've previously accepted an SSH connection to a remote computer and that remote computer's digital fingerprint or SHA256 hash key has changed since you last connected. Thus when you try to SSH again or use github to pull code, which also uses SSH, you get an error. Why? Because you're using the same remote computer address as before but the remote computer is responding with a different fingerprint. Therefore, it's possible that someone is spoofing the computer you previously connected to. This is a security issue.
If you're 100% sure that the remote computer isn't compromised, hacked, being spoofed, etc then all you need to do is delete the entry in your known_hosts file for the remote computer. That will solve the issue as there will no longer be a mismatch with SHA256 fingerprint IDs when connecting.
On Mac here's what I did:
1) Find the line of output that reads RSA host key for servername:port has changed and you have requested strict checking. You'll need both the servername and potentially port from that log output.
2) Back up the SSH known hosts file cp /Users/yourmacusername/.ssh/known_hosts /Users/yourmacusername/.ssh/known_hosts.bak
3) Find the line where the computer's old fingerprint is stored and delete it. You can search for the specific offending remote computer fingerprint using the servername and port from step #1. nano /Users/yourmacusername/.ssh/known_hosts
4) CTRL-X to quit and choose Y to save changes
Now type ssh -p port servername and you will receive the original prompt you did when you first tried to SSH to that computer. You will then be given the option to save that remote computer's updated SHA256 fingerprint to your known_hosts file. If you're using SSH over port 22 then the -p argument is not necessary.
Any issues you can restore the original known_hosts file: cp /Users/yourmacusername/.ssh/known_hosts.bak /Users/yourmacusername/.ssh/known_hosts
As many have already said, use ssh-keygen, i.e.
ssh-keygen -R pong
Also, you may like to consider temporarily turning off host key checking:
ssh -oStrictHostKeyChecking=no root#pong
Works for me!
Error: Offending RSA key in /var/lib/sss/pubconf/known_hosts:4
This indicates you have an offending RSA key at line no. 4
Solution 1:
1. vi /var/lib/sss/pubconf/known_hosts
2. remove line no: 4.
3. Save and Exit, and Retry.
Solution 2:
ssh-keygen -R "you server hostname or ip"
OR
Solution 3:
sed -i '4d' /root/.ssh/known_hosts
This will remove 4th line of /root/.ssh/known_hosts in place(-i).
I used the solution of mockinterface, though the sed -i didn't quite work
I solved it by deleting the line by hand with vim:
sudo vim /var/lib/sss/pubconf/known_hosts
You can use any other text editor you want, but probably you'll need to show your administrative privileges
FINAL Solution!
It is showing due to the stored invalid ECDSA key. So we have to remove the ECDSA key from our master/controller machine by using the below command:
ssh-keygen -R 192.168.0.132
Here 192.168.0.132 is the remote system IP.
Edit /home/hostname /.ssh/known_hosts,and delete the 4 lines, and save it.
Then run ssh root#pong again, you will see message like this:Are you sure you want to continue connecting (yes/no)? yes, just print yes.
Note: If you got some problem, read the hints first, it will help.
The other answers here are good and working, anyway, I solved the problem by deleting ~/.ssh/known_hosts. This certainly solves the problem, but it's probably not the best approach.
updated your ssh key, getting the above message is normal.
Just edit ~/.ssh/known_hosts and delete line 4, as the message pointed you
Offending RSA key in /Users/isaacalves/.ssh/known_hosts:4
or use ssh-keygen to delete the invalid key
ssh-keygen -R "you server hostname or ip"
This is because your remote computer settings have changed. Remove your current keys for that.
vim /root/.ssh/known_hosts
Delete the line of the IP you are connecting.
In my case it happened because I previously had ssh connection with a machine with same ip(say 192.152.51.10) and the system was considering the RSA key(stored in /home/user_name/.ssh/known_hosts) of the previous host which resulted in mismatch.
To resolve this issue, you have to remove previously stored RSA key for the ip 192.152.51.10.
ssh-keygen -f "/home/user_name/.ssh/known_hosts" -R 192.152.51.10
Simple one-liner solution, tested on mac:
sed '/212.156.48.110/d' ~/.ssh/known_hosts > ~/.ssh/known_hosts
Deletes only the target ssh host IP from know hosts.
where 212.156.48.110 is replaced by the target host IP address.
Cause: Happened because the target IP was already known for a different machine due to port forwarding. Deleting the target IP before connecting will fix the issue.
I use PowerShell in Windows 10 for ssh.
My problem was in the Windows directory: C:\Users\youruser\.ssh
Delete the file known_hosts in that directory to forget the old value.
You may also use use File Explorer to locate and delete the file.
If you are trying to connect to running docker container on port 2222 with the command and you get the error
mian#tdowrick2~$ ssh pos#localhost -p 2222
Then to solve this problem, on your local computer (i.e. host machine not container) go to cd ~/.ssh/ and open known_hosts file with text editor. Remove the line starting with [localhost]:2222 and save the file. Now try to ssh again
mian#tdowrick2~$ ssh pos#localhost -p 2222
Error will disappear but you have to do it each time the container restart.
My solution is:
vi ~/.ssh/known_hosts
delete the line that contains your want connected ip.
This is better than delete all of the known_hosts
Remove that the entry from known_hosts using:
ssh-keygen -R *ip_address_or_hostname*
This will remove the problematic IP or hostname from known_hosts file and try to connect again.
From the man pages:
-R hostname
Removes all keys belonging to hostname from a known_hosts file. This option is useful to delete hashed hosts (see the -H option
above).
Sometimes, if for any reason, you need to reinstall a server, when connecting by ssh we will find that you server say that the identification has changed.
If we know that it is not an attack, but that we have reinstated the system, we can remove the old identification from the known_hosts using ssh-keygen:
ssh-keygen -R <host/ip:hostname>
root/.ssh/known_hosts updated.
Original contents retained as /root/.ssh/known_hosts.old
When connecting again we will ask you to validate the new fingerprint:
ssh -l user <host/ip:hostname>
The authenticity of host '<host/ip:hostname>' can't
be established.
RSA key fingerprint is 3f:3d:a0:bb:59:24:35:6d:e5:a0:1a:3f:9c:86:81:90.
Are you sure you want to continue connecting (yes/no)? yes
Use this command:
truncate -s 0 /home/SYSTEM_NAME/.ssh/known_hosts
I had this problem, and the reason is very simple, I have a duplicated IP address to ssh login, so after modify this problem, everthing is solved.
Only client side problem(duplicate key for ip):
Solve variants:
For clear one ip(default port 22):
ssh-keygen -f -R 7.7.7.7
For one ip(non default port):
ssh-keygen -f -R 7.7.7.7:333
Fast clear all ips:
cd ~; rm .ssh/known_hosts
7.7.7.7 - ssh your server ip connect
333 - non standart port
Just do:
cd /home/user/.ssh/ -> here user will be your username, i.e. /home/jon/ for example.
Then
gedit known_hosts & and delete the contents inside it.
Now ssh again, it should work.
I had the same error in my machine, and I clear the known_hosts file, and after that, it works fine.
Simply clear the known_hosts which is present in /home/{username}/.ssh/known_hosts
vi /home/{username}/.ssh/known_hosts
remove every line inside known hosts and exit after that you will be able to login.
OR
run this command
ssh-keygen -R "hostname/ip_address"
SOLUTION:
1- delete from "$HOME/.ssh/known_hosts" the line referring to the host towards which is impossible to connect.
2- execute this command: ssh-keygen -R "IP_ADDRESSorHOSTNAME" (substitute "IP_ADDRESSorHOSTNAME" with your destination ip or destination hostname)
3- Retry ssh connection (if it fails please check permission on .ssh directory, it has to be 700)
My solution on UBUNTU (linux):
1.You have to delete the content from "known_hosts" file which is in "/home/YOUR_USERNAME/.ssh/known_hosts"
2.Generate a new ssh key like "ssh-keygen -t rsa -C "your.email#example.com" -b 4096"
3.Copy-paste your new ssh key in your git repository (gitlab in my case) SSH keys.
It works for me !
AWS EC2.
Find the ip in the message it gives you.
run
vim /home/ec2-user/.ssh/known_hosts
Use the arrow keys to find the ip from the message and click.
dd
This will delete that line then run escape
:wp
This will save then you are good to go.
I am writing a script using boto and Python to automatically launch an Amazon EC2 instance and interact with it using SSH. Everything works fine except that every time I establish the connection, SSH prompts me to confirm the authenticity of the host like this:
The authenticity of host 'ec2-174-129-121-25.compute-1.amazonaws.com (174.129.121.25)' can't be established.
RSA key fingerprint is 26:09:bd:21:4f:55:20:3f:0d:fc:5f:cc:3e:08:30:db.
Are you sure you want to continue connecting (yes/no)?
My SSH command is:
ssh -i ssh2.pem root#ec2-174-129-121-25.compute-1.amazonaws.com
Since every EC2 instance is a new host, I have to confirm this every time, but I want an automatic script without any user input. What is the best solution?
Use -O StrictHostKeyChecking=no and, optionally, set the KnownHostsFile of /dev/null (if you want to be totally insecure about things). But remember, you're bypassing security measures meant to protect you!
edit and probably CheckHostIP=no too. man ssh and see all the gory bits.
For PuTTY and windows you can use
echo y | plink -pw yourpassword root#yourservername.com