Ssh – PuTTY cannot connect but WinSCP and Git bash can

puttyssh

I have a problem: I've been given an account on a testing-box. My public RSA key has been added to my account and I can connect just fine using programs such as WinSCP or Git bash. However, when I try to use PuTTY, like I always do, the server immediately closes the connection, only displaying Server unexpectedly closed network connection.

WinSCP also has a feature to open the current connection using PuTTY. Note: I am already successfully connected to the server at this point using my username and public-key. However, this results in the same Server unexpectedly closed network connection message immediately.

I have tried to connect to the server with no credentials pre-entered but was unable to do so either (same message).

What reason could this have, and how can this be resolved?

Best Answer

Newer versions of Putty comes with updated protocols that some ssh servers are using actually. Updating the version to the latest available could solve the issue.

Related Solutions

How to Remove Strict RSA Key Checking in SSH and Understand the Issues

Please don't delete the entire known_hosts file as recommended by some people, this totally voids the point of the warning. It's a security feature to warn you that a man in the middle attack may have happened.

I suggest you identify why it thinks something has changed, most likely an SSH upgrade altered the encryption keys due to a possible security hole. You can then purge that specific line from your known_hosts file:

sed -i 377d ~/.ssh/known_hosts

This deletes line 377 as shown after the colon in the warning:

/home/emerson/.ssh/known_hosts:377

Alternatively you can remove the relevant key by doing the following

ssh-keygen -R 127.0.0.1 (obviously replace with the server's IP)

Please DO NOT purge the entire file and ensure this is actually the machine you want to be connecting to prior to purging the specific key.

SSH – How to Recover from ‘Too Many Authentication Failures for User Root’

Are you sure that root login to ssh is allowed?

Check sshd_config and verify that root login is permitted. sshd will need to be restarted if the setting changes.

Best Answer

Related Solutions

How to Remove Strict RSA Key Checking in SSH and Understand the Issues

SSH – How to Recover from ‘Too Many Authentication Failures for User Root’

Related Topic