FAQ Search Today's Posts Mark Forums Read
» Video Reviews

» Linux Archive

Linux-archive is a website aiming to archive linux email lists and to make them easily accessible for linux users/developers.


» Sponsor

» Partners

» Sponsor

Go Back   Linux Archive > CentOS > CentOS

 
 
LinkBack Thread Tools
 
Old 09-14-2012, 03:38 PM
Dennis Jacobfeuerborn
 
Default ssh_exchange_identification: Connection closed by remote host

On 09/14/2012 05:09 PM, M. Fioretti wrote:
> Greetings,
>
> 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
> provider).

Check the /var/log/secure log. It could be that some bot is trying to brute
force your server and the daemon is hitting the session limit.

Regards,
Dennis

_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 09-14-2012, 04:06 PM
"M. Fioretti"
 
Default ssh_exchange_identification: Connection closed by remote host

On Fri, September 14, 2012 5:32 pm, Scott Silva wrote:

> Could the server A have a firewall that had allow ranges for your
> original ip range? Or denyhosts... something like that

No, there are no such settings.

Answering to other questions:

> have you checked with your ADSL provider, to
> see if they're blocking ssh traffic?

no, because as I said in my original message, I **can** do ssh traffic. I
am doing it right now, on the other Centos server. It is only one of them
that became unreachable.

> Check the /var/log/secure log
> Check your tcp_wrapper configuration

of course I can't do it right now, exactly because... I can't connect to
the server. But I will pass along these and all other similar suggestions
to the VPS provider help desk, since they will surely save time, so thanks
for these and any other tips that may come!

Marco

_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 09-14-2012, 07:50 PM
"M. Fioretti"
 
Default ssh_exchange_identification: Connection closed by remote host

On Fri, September 14, 2012 9:06 pm, Karl Vogel wrote:
>>> On Fri, 14 Sep 2012 17:09:46 +0200 (CEST),
>>> "M. Fioretti" <mfioretti@nexaima.net> said:
>
> M> Yesterday I completed (fingers crossed) the switch to a different ADSL
> M> provider. From the moment I turned on the modem on the new ADSL line, I
> M> became unable to ssh into server A. All attempts abort with this
> M> message:
> M> ssh_exchange_identification: Connection closed by remote host
>
> This is in the "grasping at straws" category, but have you tried
> connecting with a different cipher, like "blowfish" or "3des-cbc"?

I confess I had forgotten that this option existed. However, I just tried
both cyphers and there is no difference. Thanks for the other suggestion,
I'll try that as the server is reachable again.

Marco

_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 09-14-2012, 08:09 PM
 
Default ssh_exchange_identification: Connection closed by remote host

M. Fioretti wrote:
>
> On Fri, September 14, 2012 9:06 pm, Karl Vogel wrote:
>>>> On Fri, 14 Sep 2012 17:09:46 +0200 (CEST),
>>>> "M. Fioretti" <mfioretti@nexaima.net> said:
>>
>> M> Yesterday I completed (fingers crossed) the switch to a different
>> ADSL M> provider. From the moment I turned on the modem on the new ADSL
line,
>> M> I became unable to ssh into server A. All attempts abort with this
>> M> message:
>> M> ssh_exchange_identification: Connection closed by remote host
>>
<snip>
> both cyphers and there is no difference. Thanks for the other suggestion,
> I'll try that as the server is reachable again.

It's now reachable? Sounds to me as though your provider, or hosting
provider, had something screwed up and just fixed it.

mark

_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 09-14-2012, 08:21 PM
"M. Fioretti"
 
Default ssh_exchange_identification: Connection closed by remote host

On Fri, September 14, 2012 10:09 pm, m.roth@5-cent.us wrote:

>> I'll try that as the server is reachable again.
>
> It's now reachable?

No, it's not, sorry for the confusion. I meant to write "as soon as the
server is reachable again"

Marco
_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 09-14-2012, 08:45 PM
 
Default ssh_exchange_identification: Connection closed by remote host

M. Fioretti wrote:
>
> On Fri, September 14, 2012 10:09 pm, m.roth@5-cent.us wrote:
>
>>> I'll try that as the server is reachable again.
>>
>> It's now reachable?
>
> No, it's not, sorry for the confusion. I meant to write "as soon as the
> server is reachable again"
>
Have you spoken with support from the host/provider?

mark

_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 09-15-2012, 05:01 AM
"M. Fioretti"
 
Default ssh_exchange_identification: Connection closed by remote host

On Fri, September 14, 2012 11:48 pm, Stephen Harris wrote:

> 1) What happens if you run "telnet yourhost 22".

this is what happens (with the proper IP of course):

> Trying 1.2.3.4...
> Connected to yourhost (1.2.3.4)
> Escape character is '^]'.
> Connection closed by foreign host.
>
> 2) How quickly does the "closed" occur?

I'd say 4/5 seconds

> 3) What is the output of "ssh -v yourhost"

here it is, obviously with changed server name and IP

################################################## ###
[marco@avalon ~]$ ssh -v -p xxx me@example.com
OpenSSH_5.8p2, OpenSSL 1.0.0j-fips 10 May 2012
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to example.com [ip.of.example.com] port xxx.
debug1: Connection established.
debug1: identity file /home/marco/.ssh/id_rsa type -1
debug1: identity file /home/marco/.ssh/id_rsa-cert type -1
debug1: identity file /home/marco/.ssh/id_dsa type -1
debug1: identity file /home/marco/.ssh/id_dsa-cert type -1
ssh_exchange_identification: Connection closed by remote host
################################################## #########

I have informed the provider, and am waiting answers from them.

Thanks,
Marco

_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 09-15-2012, 05:04 AM
"M. Fioretti"
 
Default ssh_exchange_identification: Connection closed by remote host

On Sat, September 15, 2012 4:00 am, Paul Tader wrote:

> Can you post the (sanitized ) output from "ssh -vv my mybadhost.com" ?

Such output is exactly the same I get with only one "v" and already posted
in an earlier reply this morning

Thanks,
Marco
_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 09-18-2012, 12:56 PM
Giles Coochey
 
Default ssh_exchange_identification: Connection closed by remote host

On 14/09/2012 17:06, M. Fioretti wrote:


of course I can't do it right now, exactly because... I can't connect to
the server. But I will pass along these and all other similar suggestions
to the VPS provider help desk, since they will surely save time, so thanks
for these and any other tips that may come!



Well you can... ssh into B and then try to ssh from B to A...

--
Regards,

Giles Coochey, CCNA, CCNAS
NetSecSpec Ltd
+44 (0) 7983 877438
http://www.coochey.net
http://www.netsecspec.co.uk
giles@coochey.net


_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 

Thread Tools




All times are GMT. The time now is 05:31 AM.

VBulletin, Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO ©2007, Crawlability, Inc.
Copyright 2007 - 2008, www.linux-archive.org