When using SSH this error may show it's ugly head on occasion. Many searches for the issues point to funny TCP connection tweaks or that sshd needs to be re-configured. This is not the case.
Connecting to SSH servers gives this message:
$ ssh atom@example.com ssh_exchange_identification: Connection closed by remote host
Or maybe this if using verbose mode.
$ ssh -v atom@example.com OpenSSH_4.7p1, OpenSSL 0.9.8g 19 Oct 2007 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug1: Connecting to example.com [10.65.0.2] port 22. debug1: Connection established. debug1: identity file /home/atom/.ssh/identity type -1 debug1: identity file /home/atom/.ssh/id_rsa type 1 debug1: identity file /home/atom/.ssh/id_dsa type -1 ssh_exchange_identification: Connection closed by remote host
Try re-learning the host identity first after seeing the above message message:
$ cd ~/.ssh/ $ mv known_hosts known_hosts.tmp
When you re-connect you will be prompted to accept the host identity again.