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Muhammad_57196's avatar
Muhammad_57196
Icon for Nimbostratus rankNimbostratus
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
management
monitoring
  • hoolio's avatar
    hoolio
    Icon for Cirrostratus rankCirrostratus
    Aug 10, 2009
    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

     

  • Elias_O_16228's avatar
    Elias_O_16228
    Icon for Nimbostratus rankNimbostratus
    Sep 18, 2012
    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
  • Gilles_MOULIN_1's avatar
    Gilles_MOULIN_1
    Icon for Nimbostratus rankNimbostratus
    Sep 30, 2015

    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.