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Muhammad_57196's avatar
Muhammad_57196
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Aug 10, 2009

SSH weird problem

Hi,

 

 

I had a weird problem while trying to SSH to one of the F5. Sometime it works fine with SSH and sometime i got the following message:

 

 

"ssh_exchange_identification: Connection closed by remote host".

 

 

But nothing is being changed on that F5. I am not sure why is it let me in via SSH sometime but gave the above error message when i tried to do SSH.

 

 

Can anyone please help me. Forgive me if i paste this in the wrong forum.

 

 

Regards,

 

 

Muhammad

3 Replies

  • Hi Muhammad,

     

     

    I think this is an issue specific to SSHD--not much of anything to do with BIG-IP. You could try searching the web for this error message. There are quite a few forum posts with troubleshooting suggestions. You could try running a new instance of sshd with debug enabled:

     

     

    http://mrraph.net/WordPress/?p=16

     

     

    /usr/sbin/sshd -d -p 2200

     

     

    and then connect on port 2200. Or you could change the LogLevel in /config/ssh/sshd_config to debug, reload the config using kill -HUP `pidof sshd`and then retest.

     

     

    Here are some related links:

     

     

     

    http://archive.netbsd.se/?ml=openssh-unix-dev&a=2007-10&t=5430083

     

     

    I suspect you're hitting the MaxStartups unauthenticated connection

     

    limit. It default is 10, try bumping it on the servers to, say, 30 or 40.

     

     

     

     

     

    http://lists.mindrot.org/pipermail/openssh-unix-dev/2008-February/026176.html

     

     

    > Hi,

     

    >

     

    > I'm getting this error when I ssh to the servers.

     

    > ssh_exchange_identification: Connection closed by remote host

     

    >

     

    > I added /etc/hosts.allow and it actually worked once and if I tried again I get the same error.

     

     

    You did not mention whether you added by name or by IP.

     

    Every time I've seen this error it has been a DNS problem. And I only

     

    see this on systems that are in hosts.allow by name.

     

     

     

     

    Aaron

     

  • I just wanted to add my comment on this old thread because I ran into similar issue when I was synchronizing FIPS Security Domain "ssh_exchange_identification: Connection closed by remote host" and was able to fix it by going to system>platform>ssh IP allowed: ensure the the peer ip address is added or "select allow all"

     

     

    Regards

     

    Elias_O
  • If you are trying to connect to self IP (no managment IP) on LTM running V10, it may fails on the non default route-domain. I faced such issue when exchanging key with a GTM (bigip_add). Afterward, the iquery connection can use any self ip.