在 Mac OSx 上通过 SSH 连接到 EC2 时出现权限错误

Question

I am new to EC2. I created my security credentials from this site:

http://paulstamatiou.com/how-to-getting-started-with-amazon-ec2

It worked great, I rebooted and now when I try to connect I get a login/password prompt. (Which I never set up.) After several attempts I get this error:

Permission denied (publickey,gssapi-with-mic).

What am I doing wrong?

Answer 1

Two possibilities I can think of, although they are both mentioned in the link you referenced:

1. You're not specifying the correct SSH keypair file or user name in the ssh command you're using to log into the server:

   ssh -i [full path to keypair file] root@[EC2 instance hostname or IP address]

2. You don't have the correct permissions on the keypair file; you should use

   chmod 600 [keypair file]

to ensure that only you can read or write the file.

Try using the -v option with ssh to get more info on where exactly it's failing, and post back here if you''d like more help.

[Update]: OK, so this is what you should have seen if everything was set up properly:

debug1: Authentications that can continue: publickey,gssapi-with-mic
debug1: Next authentication method: publickey
debug1: Trying private key: ec2-keypair
debug1: read PEM private key done: type RSA
debug1: Authentication succeeded (publickey).

Are you running the ssh command from the directory containing the ec2-keypair file ? If so, try specifying -i ./ec2-keypair just to eliminate path problems. Also check "ls -l [full path to ec2-keypair]" file and make sure the permissions are 600 (displayed as rw-------). If none of that works, I'd suspect the contents of the keypair file, so try recreating it using the steps in your link.

Answer 2

The key for me to be able to connect was to use the "ec2-user" user rather than root. Ie:

ssh -i [full path to keypair file] ec2-user@[EC2 instance hostname or IP address]

Answer 3

+1

I noticed that for some AMIs like Amazon Linux, ec2-user@xxx.XX.XX.XXX would work. But for an ubuntu image, I had to use ubuntu@ instead. It was never a problem with the .pem, just with the user name.

Answer 4

I had met this problem too.And I found that happend beacuse I forgot to add the user-name before the host name: like this:

ssh -i test.pem ec2-32-122-42-91.us-west-2.compute.amazonaws.com

and I add the user name:

ssh -i test.pem ec2-user@ec2-32-122-42-91.us-west-2.compute.amazonaws.com

it works!

Answer 5

In my case it's because the permission for my home directory is 775, and SSH is not happy about it. It should work after executing:

server$ chmod go-w ~/
server$ chmod 700 ~/.ssh
server$ chmod 600 ~/.ssh/authorized_keys

I had very similar experience this afternoon. I was setting up django on EC2, and suddenly I cannot SSH into the box anymore. Glad I still had an active connection, so I modified /etc/ssh/sshd_config to set:

PasswordAuthentication yes

and set password for ec2-user , then I can login by entering the password.

However, after some googling I found this thread: http://ubuntuforums.org/showthread.php?t=577279 . It turned out that during my setup of django I changed the permission for my home directory, and SSH is very strict about this. So the file permission must be set correctly.

Answer 6

Tagging on to mecca831's answer:

ssh -v -i generated-key.pem ec2-user@11.11.11.11

[ec2-user@ip-11.11.11.11 ~]$ sudo passwd ec2-user newpassword newpassword

[ec2-user@ip-11.11.11.11 ~]$ sudo vi /etc/ssh/sshd_config Modify the file as follows:

    # To disable tunneled clear text passwords, change to no here!
    PasswordAuthentication yes
    #PermitEmptyPasswords no
    # EC2 uses keys for remote access
    #PasswordAuthentication no

Save

[ec2-user@ip-11.11.11.11 ~]$ sudo service sshd stop [ec2-user@ip-11.11.11.11 ~]$ sudo service sshd start

you should be able to exit and ssh in as follows:

ssh ec2-user@11.11.11.11

and be prompted for password no longer needing the key.

Answer 7

Are you sure you have used the right instance? I ran into this problem and realized that something like 4 of the ubuntu instances i tried did not have SSH servers installed on them.

For a list of good servers see "Getting the images" about half way down. Sounds like you may be using something else... the default username is ubuntu on these images.

https://help.ubuntu.com/community/EC2StartersGuide

Answer 8

After about a half hour of searching and trying to debug this I was able to figure it out. My situation involved me using the same pem file for two different ec2 instance and it working for one and not the other.

My first instance it worked on was the standard aws linux ami amzn-ami-hvm-2014.03.2.x86_64-ebs. I simply used

ssh -i mypemfile.pem ec2-user@myec2ipaddress 

and it worked.

I then launched a fedora instance Fedora-x86_64-19-20140407-sda and tried the same command but kept getting:

Permission denied (publickey,gssapi-keyex,gssapi-with-mic).

After changing my username from ec2-user to fedora it worked!

ssh -i mypemfile.pem fedora@myec2address

Answer 9

I was able to login using ec2-user

ssh -i [full path to keypair file] ec2-user@[EC2 instance hostname or IP address]

Answer 10

None of the above helped me, but futzing with the user seemed like it had promise. For my config using 'ubuntu' was right.....

ssh -i [full path to keypair file] ubuntu@[EC2 instance hostname or IP address]

Answer 11

I recommend against setting a password as some other answers suggest. Using the key file is both safer (no one can guess your passwords) and more convenient (once you set up a config file). Here's a basic ~/.ssh/config :

Host my-ec2-server
  HostName 11.11.11.11
  User ec2-user
  IdentityFile /path/to/generated-key.pem

Now you can just type ssh my-ec2-server and you're in! And as also mentioned in other answers, use -v to get extra info when your connection isn't working.

Answer 12

If the issue is consistent and happened about 10-15 times in a row even after changing file permissions to 400 or 600, then it is most certainly something is wrong on the ec2 instance, so to make sure:

1. Check the logs when you try to ssh to the instance by adding -v at the end and see either it gives out anything specific.

2. Make sure you use the correct name for ssh, like Ubuntu. Perhaps that depends on Linux distribution and users you added and either you've given permission for "root user" ssh.

Then if nothing helps, follow the documentation here https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/TroubleshootingInstancesConnecting.html#TroubleshootingInstancesConnectingMindTerm to fix that. It helped in my case, and it happened because of messed up directories/files permissions.

Answer 13

I had the same problem using the AWS Toolkit for Eclipse. I created the Getting Started instance OK and opened a shell. However, the user was set to ec2-user. I used the Open Shell As... command and set the user to root. Then it worked.

Answer 14

Had a similar issue. Here are the steps used to setup SSH keys and forwarding on the Mac. Made these notes for myself - may help someone... check against your config.

The assumption here is there are no keys setup. If you already have the keys setup skip this section.

$ ssh‐keygen ‐t rsa ‐b 4096

Generating public/private rsa key pair.

Enter a file in which to save the key (/Users/you/.ssh/id_rsa): [Press enter] Enter passphrase (empty for no passphrase): [Type a passphrase] Enter same passphrase again: [Type passphrase again]

Modify ~/.ssh/config adding the entry for the key file:

~/.ssh/config should look similar to:

Host *

AddKeysToAgent yes

UseKeychain yes

IdentityFile ~/.ssh/id_rsa

Store the private key in the keychain:

$ ssh‐add ‐K ~/.ssh/id_rsa

Go test it now with: ssh -A username@yourhostname

Should forward your key to yourhostname. Assuming your keys are added on you should connect without issue.

Answer 15

If you have a PPK file working on a PC, then export it as OpenSSH file using puttygen.exe for PC and use that on Mac (any Unix machine).

I was getting the same error --

debug1: Authentications that can continue: publickey,gssapi-with-mic
debug1: Next authentication method: publickey
debug1: Trying private key: ec2-keypair
debug1: read PEM private key done: type RSA
debug1: Authentications that can continue: publickey,gssapi-with-mic
debug1: No more authentication methods to try.
Permission denied (publickey,gssapi-with-mic)

As I was using a PPK file on Windows, I followed the steps as described above and Bingo!

$ ssh -i ec2-openssh-key root@ec2-instance-ip

Answer 16

I was getting this error when I was trying to ssh into an ec2 instance on the private subnet from the bastion, to fix this issue, you've to run (ssh-add -K) as follow.

    Step 1: run "chmod 400 myEC2Key.pem"
    Step 2: run "ssh-add -K ./myEC2Key.pem" on your local machine
    Step 3: ssh -i myEC2Key.pem root@ec2-107-20-4-100.compute-1.amazonaws.com
    Step 4: Now try to ssh to EC2 instance that is on a private subnet without specifying the key, for example, try ssh ec2-user@ipaddress.

    Hope this will help.
Note: This solution is for Mac.