SSH problem - Read from socket failed: Connection reset by peer

1. start monitoring the server's log file

   tail -f /var/log/auth.log

2. add -v to get a verbose output at the client end

   ssh user@computerB -v

This might give you more details about the cause. if the rsa and dsa keys are missing on the server, fix them by:

ssh-keygen -t rsa1 -f /etc/ssh/ssh_host_rsa_key
ssh-keygen -t dsa  -f /etc/ssh/ssh_host_dsa_key

I re-installed the SSH bits by doing:

sudo apt-get --reinstall install openssh-server openssh-client

This fixed all my problems.

änthräX's method is very helpful. It works for me!

Basically I think, after installed ssh, key files are needed.

The only revision I made was to use rsa instead of rsa1:

ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key 
ssh-keygen -t dsa -f /etc/ssh/ssh_host_dsa_key

That modified method worked for me.

It's because somehow the permissions of the files inside /etc/ssh have changed... So change the permission of the files like the example given below:

use:

chmod 644 ssh_config
chmod 600 moduli

and so on...

Finally the file permissions should look like something like given below,

[root@hostname ssh]# ls -latr
total 172

-rw-r--r--.   1 root root   2047 Aug 12  2010 ssh_config
-rw-------.   1 root root 125811 Aug 12  2010 moduli
-rw-------.   1 root root    963 Mar  1 16:02 ssh_host_key
-rw-r--r--.   1 root root    627 Mar  1 16:02 ssh_host_key.pub
-rw-r--r--.   1 root root    382 Mar  1 16:02 ssh_host_rsa_key.pub
-rw-------.   1 root root   1675 Mar  1 16:02 ssh_host_rsa_key
-rw-r--r--.   1 root root    590 Mar  1 16:02 ssh_host_dsa_key.pub
-rw-------.   1 root root    668 Mar  1 16:02 ssh_host_dsa_key
-rw-------.   1 root root   3845 May  7 11:52 sshd_config

After changing the permissions try connecting from putty, should work fine..