Tuesday, July 10, 2007

SSH without password

Using the below steps, you can ssh to the server from client without the entering any password.
The machine which run the ssh command is the client
The machine that the client access using ssh is the server
  1. Run the following command on the client
    • -> ssh-keygen -t dsa
  2. File id_dsa and id_dsa.pub will be created inside $HOME/.ssh
  3. Copy id_dsa.pub to the server's .ssh directory
    • -> scp $HOME/.ssh/id_dsa.pub user@server:/home/user/.ssh
  4. Change to /root/.ssh and create file authorized_keys containing id_dsa content
    • -> cd /home/user/.ssh
    • -> cat id_dsa >> authorized_keys
  5. Change "StrictModes yes" in /etc/ssh/sshd_config to "StrictModes no"
  6. Restart ssh server
  7. You can try ssh to the server from the client and no password will be needed
    • -> ssh user@server
Another alternative to the above steps is to use ssh-copy-id command. The steps are:
  1. Run the following command on the client
    • -> ssh-keygen -t dsa
  2. File id_dsa and id_dsa.pub will be created inside $HOME/.ssh
  3. Copy the id_dsa.pub to the server's .ssh directory
    • -> ssh-copy-id -i ~/.ssh/id_dsa.pub user@server
  4. Change "StrictModes yes" in /etc/ssh/sshd_config to "StrictModes no"
  5. Restart ssh server
  6. You can try ssh to the server from the client and no password will be needed
    • -> ssh user@server
Thanks to nailer for this information
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10 comments:

  1. AnonymousFebruary 19, 2009

    Wonderful. I've been searching for this for several days. Clear and easy to understand. Thanks.

    ReplyDelete
  2. AnonymousJune 11, 2009

    Awesome! Straight to the point! Thanks!

    ReplyDelete
  3. sjoshiAugust 08, 2009

    Hi, I tried the same thing but it doesn't seem to work on RedHat linux... it is still asking me for the password. Do I have to change the configuration or permissions somewhere for this to work?

    ReplyDelete
  4. blackorgaAugust 12, 2009

    Hi sjoshi,

    This method was tested on CentOS, which can be regarded as Redhat Linux's twin. You can try restarting the server's sshd, if following the method still fails. Thanks

    ReplyDelete
  5. AnonymousAugust 06, 2010

    Should the name of the file in remoteserver .ssh/authorized_keys.
    Is there anyway to configure the file name?

    ReplyDelete
  6. Alexey DementyevSeptember 04, 2011

    #!/usr/bin/expect -f

    if { [llength $argv] < 3 } {
    send "Usage: ssh2 \n"
    exit;
    }

    set host [lrange $argv 0 0]
    set user [lrange $argv 1 1]
    set pass [lrange $argv 2 2]
    set supass [lrange $argv 3 3]

    set timeout -1

    spawn ssh $user@$host
    match_max 100000

    expect {
    "*yes/no*" {
    send -- "yes\r"
    exp_continue
    }
    "*?assword:*" {
    send -- "$pass\r"
    }
    }
    interact

    ReplyDelete
  7. daemonSeptember 07, 2011

    how do i ssh myself without password

    ReplyDelete
  8. AnonymousAugust 07, 2012

    https://access.redhat.com/knowledge/solutions/8761

    ReplyDelete
  9. AnonymousAugust 07, 2012

    https://access.redhat.com/knowledge/solutions/8761

    ReplyDelete
  10. АндрейNovember 19, 2012

    "Change "StrictModes yes" in /etc/ssh/sshd_config to "StrictModes no" -- thank you -- that's what I need! I've lost half an hour trying to make ssh auth work.

    ReplyDelete