Difference between revisions of "SSH"

 
Line 1: Line 1:
Difficulty: 3
 
  
SSH without a password : Public-key authentication (UNIX and Mac OS X)
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Difficulty: 2
  
To execute this solution, the reader should:  
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SSH from Windows : PuTTY
  
      be comfortable with the command line
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  1.Find and download putty.exe on this page:
  
 +
    http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html
  
Note: Logging in without a password will save you a few seconds out of every day. It comes however, with an added security risk: if someone compromises your
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    The program doesn't need to be installed; just open the file you downloaded whenever you want to run PuTTY.
machine, they can then log into WSO with your account. If you are willing to bear this responsibility, then read on.
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  2.Open putty.exe
 +
  3.Enter "wso.williams.edu" for the host, and "SSH" for the protocol.
 +
  4.Click "Open"
 +
  5.Enter your WSO login and password when prompted.
 +
  6.If this is your first time connecting from this computer, you might get a message like this:
  
The basic idea is that WSO's server will check for a special key on your computer every time you log in, and if it checks out, you'll be allowed in without entering a password. If
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    The server's host key is not cached in the registry. You
you'd like a more in-depth explanation, read on:
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    have no guarantee that the server is the computer you
 +
    think it is.
 +
    The server's key fingerprint is:
 +
    ssh-rsa 1024 7b:e5:6f:a7:f4:f9:81:62:5c:e3:1f:bf:8b:57:6c:5a
 +
    If you trust this host, hit Yes to add the key to
 +
    PuTTY's cache and carry on connecting.
 +
    If you want to carry on connecting just once, without  
 +
    adding the key to the cache, hit No.  
 +
    If you do not trust this host, hit Cancel to abandon the
 +
    connection.
  
http://the.earth.li/~sgtatham/putty/0.54/htmldoc/Chapter8.html#8
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    If this is your first time, don't sweat it, just say Yes. If you get this message and this is not your first time SSH'ing from this machine, you might drop us a line. For more
 +
    information about host keys, read this page:
  
Anyway, enough chit-chat. Here's how to do it:
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    http://the.earth.li/~sgtatham/putty/0.55/htmldoc/Chapter2.html
  
Adapted from http://bumblebee.lcs.mit.edu/ssh2/.
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   7.You're in! Happy computing.
 
 
   1.Open a terminal
 
  2.Generate a public key and a private key. We'll copy the public key over to the server later.
 
 
 
    $ ssh-keygen -t rsa -f ~/.ssh/id_rsa
 
 
 
  3.When it says something like Enter passphrase (empty for no passphrase):
 
    Just press return.
 
  4.Let's copy the public key to WSO. Type
 
 
 
    $ scp .ssh/id_rsa.pub user@wso:~/.ssh/.
 
 
 
  5.Cruise over to the WSO server:
 
 
 
    $ ssh user@wso.williams.edu
 
 
 
  6.Hop into the SSH directory:
 
 
 
    $ cd .ssh
 
 
 
  7.Append the key to your list of authorized keys:
 
 
 
    $ cat id_rsa.pub >> authorized_keys2
 
 
 
  8.Change permissions:
 
 
 
    $ chmod 640 authorized_keys2
 
 
 
  9.Kill the key.
 
 
 
    $ rm id_rsa.pub
 
 
 
 
 
All done! Now you can SSH and SCP to WSO without a password.
 
 
 
-Evan Miller
 

Revision as of 00:29, September 25, 2005

Difficulty: 2

SSH from Windows : PuTTY

  1.Find and download putty.exe on this page: 
    http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html 
    The program doesn't need to be installed; just open the file you downloaded whenever you want to run PuTTY. 
  2.Open putty.exe 
  3.Enter "wso.williams.edu" for the host, and "SSH" for the protocol. 
  4.Click "Open" 
  5.Enter your WSO login and password when prompted. 
  6.If this is your first time connecting from this computer, you might get a message like this: 
    The server's host key is not cached in the registry. You 
    have no guarantee that the server is the computer you 
    think it is. 
    The server's key fingerprint is: 
    ssh-rsa 1024 7b:e5:6f:a7:f4:f9:81:62:5c:e3:1f:bf:8b:57:6c:5a 
    If you trust this host, hit Yes to add the key to 
    PuTTY's cache and carry on connecting. 
    If you want to carry on connecting just once, without 
    adding the key to the cache, hit No. 
    If you do not trust this host, hit Cancel to abandon the 
    connection. 
    If this is your first time, don't sweat it, just say Yes. If you get this message and this is not your first time SSH'ing from this machine, you might drop us a line. For more
    information about host keys, read this page: 
    http://the.earth.li/~sgtatham/putty/0.55/htmldoc/Chapter2.html 
  7.You're in! Happy computing.