AWS - Disconnected No supported authentication methods available server sent publickey

Question

SSH to my AWS server just broke for both Putty and Filezilla  I m making some effort for this post to be a comprehensive troubleshooting list  so if you share links to other stack overflow pages  I ll edit them into the question   Disconnected   No supported authentication methods available  server sent  publickey     The error is familiar from when I set up the connection almost a year ago  If you re setting up AWS SSH for the first time  these address the most common problems    Wrong username  Disconnected   No supported authentication methods available  server sent  publickey  Incorrect  ppk file  Unable to connect to amazon server using putty   However  the only thing I could think that would impact a previously working system is    Wrong IP  Restarting an AWS instance  or creating an image  is not guaranteed to keep the same IP address  This would obviously have to be updated in putty     What other possibilities are there    Solution to this one  per the accepted post below  is that for AWS EC2 all 3 of these need to have proper permissions  777 not ok for any of these   Here s one example that works    home ec2-user  - 700  home ec2-user  ssh  - 600  home ec2-user  ssh authorized keys - 600    var log secure will tell you which one is throwing an error  consult this video tutorial to get access if you re completely locked out  http   d2930476l2fsmh cloudfront net LostKeypairRecoveryOfLinuxInstance mp4

User · Answer

While trying to connect to a SiteGround server via Putty I had the same problem. Their instructions are pretty thorough, and must work for some people, but didn't work for me.

They recommend running pageant.exe, which runs in the background. You register your key(s) with Pageant, and it's supposed to let Putty know about the keys when it tries to connect.

In a couple of places I found suggestions to specify the key directly in the Putty session definition: Putty Configuration > Connection > SSH > Auth > "Private key file for authentication", then browse to your key file in .ppk format.

Doing this without running Pageant resolved the problem for me.

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There is another cause that would impact a previously working system  I re-created my instances  using AWS OpsWorks  to use Amazon Linux instead of Ubuntu  and received this error after doing so  Switching to use  ec2-user  as the username instead of  ubuntu  resolved the issue for me

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Login is depending upon the AMI which you have created  Use left hand side data as a username while doing login  ubuntu- ubuntu AMIs ec2-user- Amazon Linux AMI centos- Centos AMI debian or root- Debian AMIs6 ec2-user or fedora- Fedora

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For me  I just had to tell FileZilla where the private keys were    Select Edit   Settings from the main menu In the Settings dialog box  go to Connection   SFTP Click the  Add key file     button Navigate to and then select the desired PEM file s

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in most cases  got no authentication method error when using the wrong username for logging in  But I do find something else if you still struggle with connection issue and you have tried all the options above   I created couple Linux VM and try to reproduce such connection issue  one thing I found is  when AWS asked you name your key pair  DO NOT user blank space       and dot       in key pair name  even AWS actually allow you to do so   ex  when I named the key pair as  AWS FREE LINUX   connection always be refused  When I named as  AWS FREE LINUX   everything works fine   Hope this will help a little bit

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During ssh session my connection broke  since then I cannot ssh my SRV  I had started a new instance  and I m able to ssh the new instance  with the same key    I mounted the old volume to the new machine  and check the  ssh authorized key and couldn t find any problem with permission or content

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A similar issue happened with me today  I also had searched alot about this No one help  I just made two changes and its get working properly as well    I had visited Amazon documentation where describe either Verify that there is a rule that allows traffic from your computer to port 22  SSH  and if not present  create it and edit  Security Group  and add  SSH  to my IP  This will help  In my case  In putty profile  I have to again authorize with  ppk file  I don t know why it ask again  without any changes made    Hope it will help you

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You will also receive  Disconnected   No supported authentication methods available  server sent  publickey   when you have a correct Linux user but you haven t created the file  ssh authorized keys and saved the public key as indicated in Managing User Accounts on Your Linux Instance

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In my case the problem was that the ppk file was placed in  USERPROFILE  Downloads instead of  USERPROFILE  ssh folder     After I moved the file  the problem disappeared

User · Answer

I had the same problem  by accident mistake  I ll share it here  in case someone may have made the same mistake   Basic steps  as others described    Download putty and puttygen  or the putty package and install it  Get the  pem file from your AWS EC2 instance  Use puttygen to convert the  pem file so that you ll have a private key --- mistake happened here  I chose  Conversions  tab from PuttyGen  and load my  pem file  After loading pem file  here DO NOT hit  Generate   instead directly  Save private key   That s the key you need  If you click Generate  you ll have a totally different pair of keys  In putty  use ec2-user your public dns that you get from aws ec2 instance  and load the private key at SSH Auth   Good luck

User · Answer

PuTTY does not natively support the private key format   pem  generated by Amazon EC2  PuTTY has a tool named PuTTYgen  which can convert keys to the required PuTTY format   ppk   You must convert your private key into this format   ppk  before attempting to connect to your instance using PuTTY    The steps how to perform this are described here  https   docs aws amazon com AWSEC2 latest UserGuide putty html  This solved the problem

User · Answer

Comprehensive answer is here  https   docs aws amazon com AWSEC2 latest UserGuide putty html  Your problem can be related to incorrect login which varies depending on AMIs  Use following logins on following AMIs    ubuntu or root on ubuntu AMIs ec2-user on Amazon Linux AMI centos on Centos AMI debian or root on Debian AMIs ec2-user or fedora on Fedora ec2-user or root on  RHEL AMI  SUSE AMI  other ones    If you are using OS    Windows - get PEM key from AWS website and generate PPK file using PuttyGen  Then use Putty to use the PPK  select it using left-column  Connection- SSH- Auth  Private key for authorization  Linux - run  ssh -i your-ssh-key pem login IP-or-DNS   Good luck

User · Answer

This   quot Disconnected  No supported authentication methods available  server sent  publickey  quot  happened to me after I turned on Microsoft One Drive backup and sync for my files including the directory where I saved my ssh key  In my case the solution is simple  just go to Putty   gt  SSH   gt  Auth and just  re browse again to where my same key is located and saved  then it worked  It looks backup and sync software such as Microsoft One Drive  and may be the same with Google Drive   affect the way Putty sees and identifies directories if the key directory is specified and then later some time installing or turning on backup and sync including that directory

User · Answer

I had the same problem  I used Public DNS instead of Public IP  It resolved now

User · Answer

Based on multiple instances  if the key file and username are correct  this seems to occur when changing certain directory permissions associated with the root user

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In my case the problem was with hostname public DNS I associated Elastice IP with my instance and then my DNS got changed  I was trying to connect with old DNS  Changing it to new solved the problem  You can check the detail by going to your instance and then clicking view details

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For me this error appeared immediatey after I changed the user s home directory by   sudo usermod -d var www html username   It can also happen because of lack of proper permission to authorized key file in    ssh  Make sure the permission of this file is 0600 and permission of    ssh is 700

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I am using OpsWorks and wanted to register a new existing Linux instance from my Windows machine on AWS Cli    Frist problem was  that I had to use my Putty generated  pkk file   Second problem was that I needed to quote the absolute path to that  pkk file like that      aws opsworks register --infrastructure-class ec2  --ssh-username   ec2-user --ssh-private-key  C  key ppk

[amazon-web-services] AWS - Disconnected : No supported authentication methods available (server sent :publickey)

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