[CentOS] ssh_exchange_identification: Connection closed by remote host

Fri Sep 14 15:09:46 UTC 2012
M. Fioretti <mfioretti at nexaima.net>


I have accounts on two Centos servers, A and B, each hosted on a remote
VPS by a different provider/datacenter.

Until yesterday night, I could connect without problems via SSH to both
servers from my home Fedora 16 desktop.

Yesterday I completed (fingers crossed) the switch to a different ADSL
provider. From the moment I turned on the modem on the new ADSL line, I
became unable to ssh into server A. All attempts abort with this message:

ssh_exchange_identification: Connection closed by remote host

I know that server A is still up and running, because the websites and
email services it runs are still up. Server B is still reachable via ssh,
no problem. The only difference between the two servers is that A runs
Centos 4.something, while B runs Centos 6.1

I have already done some online search on this problem, but all the pages
I have found discuss how to diagnose and fix it working on the server (*),
which is exactly what I can't do right now...

Any clues on what may have happened, and if it could be related in any way
to differences (whatever they may be) between ADSL providers, instead of a
bizarre coincidence?

Of course, I can and will ask the VPS provider to reboot the machine, but
I would also like to know your opinion on what exactly may have happened,
and how to prevent it in the future (also to pass your suggestions to the


(*) except remove the server entry from .ssh/known_hosts in my home
desktop. I did it and nothing changed