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OVH Dedicated Server, SSH suddenly stops working

Discussion in 'Dedicated server hosting' started by rdan, Dec 15, 2015.

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  1. eva2000

    eva2000 Administrator Staff Member

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    Do you have firewalls on the other server and pc you failed to connect to OVH sshd from ? ensure all those systems have whitelisted TCP and TCP6 out for 1018 port too
     
  2. rdan

    rdan Well-Known Member

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    I don't have firewall on this Linux Mint Desktop.
    But why it suddenly stops working just today when it works fine last 40 days?
    All other servers I have, all working fine except this single OVH server.
     
  3. eva2000

    eva2000 Administrator Staff Member

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    tried OVH support ? network, sshd service or server restart ?
     
  4. rdan

    rdan Well-Known Member

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    Yes, I have created ticket support already.
    Just did full server restart now.
    Same thing, doesn't work.
     
  5. eva2000

    eva2000 Administrator Staff Member

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    Yeah then not much I can do from this end. You are using CentOS distribution kernel and not OVH's custom Kernel ?
     
  6. rdan

    rdan Well-Known Member

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    Yes as always :).
    [​IMG]

    The weird thing happen now is, since I added my Desktop Public key on the server yesterday, It suddenly works now on my Desktop :D.
    But still can't connect from other system/vps that don't have public auth added.
     
  7. eva2000

    eva2000 Administrator Staff Member

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    did you disable login using passwords ?

    i.e. in set /etc/ssh/sshd_config
    Code:
    PasswordAuthentication no
     
  8. rdan

    rdan Well-Known Member

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  9. eva2000

    eva2000 Administrator Staff Member

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  10. rdan

    rdan Well-Known Member

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    What's the reason for this messed up files :(.
     
  11. eva2000

    eva2000 Administrator Staff Member

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    not sure see the version at top of the file and date, yours says 1.25 vs 1.80

    could be OVH default CentOS image is altered somewhat ?

    also notice yours doesn't have centmin mod added tweaks at very bottom i.e.
    Code:
    ClientAliveInterval 3600
    ClientAliveCountMax 120
    UseDNS no
    KexAlgorithms ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
    this is for 123.09beta01 which added ECDSA key support to OpenSSH for CentOS 6.x

    if on 123.08stable remove this line
    Code:
    KexAlgorithms ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
    so it suggests the sshd_config file you have now wasn't in place when centmin mod was initially installed, so suggests sshd_config file might have been replaced after centmin mod initial install

    check file date
    Code:
    ls -lah /etc/ssh/sshd_config
     
    Last edited: Dec 16, 2015
  12. eva2000

    eva2000 Administrator Staff Member

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  13. rdan

    rdan Well-Known Member

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    -rw------- 1 root root 3.9K Nov 3 21:53 /etc/ssh/sshd_config
     
  14. rdan

    rdan Well-Known Member

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  15. eva2000

    eva2000 Administrator Staff Member

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  16. eva2000

    eva2000 Administrator Staff Member

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  17. rdan

    rdan Well-Known Member

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  18. eva2000

    eva2000 Administrator Staff Member

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    haha you have a Ghost In The Shell :LOL:
     
  19. rdan

    rdan Well-Known Member

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  20. eva2000

    eva2000 Administrator Staff Member

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    i see you posted configs of wrong file initially, you posted contents for /etc/ssh/ssh_config and not /etc/ssh/sshd_config

    only one we need to touch/edit is /etc/ssh/sshd_config