Wiki source code of Einloggen_Ohne_PasswortEn

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1 = Logging in without a password (via SSH key) =
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3 [[Für die deutsche Version bitte hier klicken>>CIT.ITO.Docs.Guides.Helpdesk.Einloggen_Ohne_Passwort.WebHome]]
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5 Here you will learn how to log on to a university server via [[Secure Shell (SSH)>>http://en.wikipedia.org/wiki/Secure_Shell]] without having to enter a password at the login. (The most common problems are discussed in the [[FAQ section>>||anchor="FaqAnchor"]] below).
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7 * (% style="color:teal" %)Windows(%%) users will find a useful how-to for using SSH through !PuTTY [[here>>CIT.ITO.Docs.Guides.Helpdesk.Ssh_mit_PuTTYen.WebHome]].
8 * This how-to is primarily for (% style="color:teal" %)Linux/Unix (including Mac OS X)(%%) users and was created using Ubuntu.
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10 {{toc/}}
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12
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14 **WARNING:** For this tutorial we assume that you have never generated SSH keys on your system before. Please be **careful** not to overwrite existing keys.
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16 == (% style="color:green" %)1. Open a terminal on your own (not remote) system(%%) ==
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18 [[image:https://xwiki.rbg.tum.de/bin/download/Informatik/Helpdesk/Einloggen_Ohne_Passwort/WebHome/openTerminal.png||alt=""]]
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20 ----
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22 == (% style="color:green" %)2. Generate a pair of keys(%%) ==
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24 * Type into the terminal window: {{{
25 ssh-keygen -t rsa
26 }}} and press Enter.
27 * Confirm the standard filename (##id_rsa## will be generated).
28 * Set a “passphrase” for the key. This can be a longer sentence including spaces. The passphrase will be needed again shortly.
29 * The output in the terminal should look like the picture below and as a result you now have the files ##id//rsa//##// and ##id##//##rsa.pub## in your ##/.ssh/## folder.
30 [[image:https://xwiki.rbg.tum.de/bin/download/Informatik/Helpdesk/Einloggen_Ohne_Passwort/WebHome/keyCreate.png||alt=""]]
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32 ----
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34 {{id name="MyAnchor1"/}}
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36 == (% style="color:green" %)3. Copy the public key ##id_rsa.pub## onto the remote (lxhalle) system(%%) ==
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38 * Type into the terminal window ((% style="color:red" %)NOTE:(%%) If your home username differs from the lxhalle-login, substitute your username for ##`whoami`## everywhere in this tutorial) {{{
39 ssh-copy-id -i ~/.ssh/id_rsa.pub `whoami`@lxhalle.informatik.tu-muenchen.de
40 }}} and press enter.
41 * Enter the login password for the lxhalle-server ((% style="color:red" %)NOT the “passphrase”!(%%)).
42 * (% style="color:red" %)NOTE:(%%) On (% style="color:teal" %)Mac OS X(%%) or where ##ssh-copy-id## not available: Please append the ##id//rsa.pub//##// file manually to ##/.ssh/authorized##//##keys## on the target system. (Create it if it does not exist.)
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44 == (% style="color:green" %)4. Log into the remote (lxhalle) system(%%) ==
45
46 * Type {{{
47 ssh `whoami`@lxhalle.informatik.tu-muenchen.de
48 }}} and confirm.
49 * Now you will need to enter the “passphrase” that you just set.
50 {{id name="AgentAnchor"/}}
51
52 == (% style="color:green" %)5. Set the SSH agent to automatically accept the identity(%%) ==
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54 * Type {{{
55 ssh-add -l
56 }}} and hit enter.
57 * You will need to enter your “passphrase” once more.
58 * If everything went right you will be able to log onto the remote system through {{{
59 ssh lxhalle.informatik.tu-muenchen.de
60 }}} without needing to type the password. If your username on your home computer differs from the lxhalle-login, you need to enter it in front of ##lxhalle.informatik.tu-muenchen.de## so it becomes {{{
61 ssh YOUR_LXHALLE_USERNAME@lxhalle.informatik.tu-muenchen.de
62 }}}
63 {{id name="FaqAnchor"/}}
64
65 == (% style="color:green" %)6. FAQ(%%) ==
66
67 * “In [[step 3>>||anchor="MyAnchor1"]] I’m asked to accept the authenticity of the connection (first five lines of the screenshot below). What should I do?”
68 [[image:https://xwiki.rbg.tum.de/bin/download/Informatik/Helpdesk/Einloggen_Ohne_Passwort/WebHome/keyCopy.png||alt=""]]
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70 **Solution:** Just accept by typing **##yes##**.
71
72 ----
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74 * Problems with the SSH agent in [[step 5>>||anchor="AgentAnchor"]]
75 One possible problem with the SSH agent is illustrated by the screenshot below. The agent does not appear to be running.
76 [[image:https://xwiki.rbg.tum.de/bin/download/Informatik/Helpdesk/Einloggen_Ohne_Passwort/WebHome/SSHAgentError.png||alt=""]]
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78 **Solution in GNOME:** The SSH agent can be set to start automatically via //Startup Applications//. Just set the appropriate flag in the settings as shown below. You will need to log out and back in for this change to take effect.
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80 [[image:https://xwiki.rbg.tum.de/bin/download/Informatik/Helpdesk/Einloggen_Ohne_Passwort/WebHome/SSHAgentActivation.png||height="800" alt=""]]