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Comment: Client side firewall setting for krb.
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| == How to log in to mire without typing your password == | #pragma section-numbers off |
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| Zeroth, you must have openssh client 4.3 or later. Other versions may work, but we make no guarantees. You will also want the {{{krb5-user}}} package if you are using Debian or Ubuntu. | This page explains how to log in to our servers without having to type in a password. We use kerberos for this rather than RSA/DSA public keys. |
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| First, you must make sure that your `/etc/krb5.conf` (or, on MacOS, your `/Library/Preferences/edu.mit.Kerberos` file) is sane. All you need to do is make sure that there are NOT entries in there which disable the `dns_lookup_kdc` or `dns_lookup_realm` options (unfortunately Fedora ships with these crippled). If you don't see those options in the file, you're fine. | An extra benefit is that passwordless logins using kerberos are noticably faster than passwordless logins using public key authentication. This is because kerberos uses symmetric cryptography (which is faster) and requires fewer round-trips during the authentication process. |
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| Then, you must obtain kerberos tickets. If your username is "fred", you would do this by typing | [[TableOfContents]] = Prerequisites = You must have openssh client 4.3 or later. Other versions may work, but we make no guarantees. You will also want the {{{krb5-user}}} package if you are using Debian or Ubuntu. For Mac OS X 10.3 and later no additional software is required for the instructions below to work. For further details, check out ["MemberManual/TransferringFiles/OpenAFS"], and follow just the Kerberos instructions. = Instructions = Once a Kerberos client hsa been installed, you must obtain Kerberos tickets. If your username is "fred", you would do this by typing: |
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| kinit fred@HCOOP.NET | kinit fred@HCOOP.NET |
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| Then type your password when prompted. Note that you MUST capitalize HCOOP.NET and you MUST NOT capitalize your user name. This is important. | Then type your password when prompted. Note that you '''must''' capitalize HCOOP.NET and you '''must not''' capitalize your user name. This is important. |
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| klist | klist |
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| ssh -o 'GSSAPIAuthentication yes' -o 'GSSAPIDelegateCredentials yes' mire.hcoop.net | ssh -o 'GSSAPIAuthentication yes' -o 'GSSAPIDelegateCredentials yes' fred@ssh.hcoop.net |
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| If that doesn't work, add "`-vvv`" to the command line and copy and paste the ENTIRE output into an email to hcoop-discuss and we'll tell you what's up. | |
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| If you do this a lot, you can include the `GSSAPIAuthentication` and `GSSAPIDelegateCredentials` options in your `.ssh/config` file. But you should NOT turn on `GSSAPIDelegateCredentials` for arbitrary hosts (make sure you only enable it for HCOOP hosts). Here's what AdamMegacz uses: | = Automating things = If you do this a lot, you can include the `GSSAPIAuthentication` and `GSSAPIDelegateCredentials` options in your `~/.ssh/config` file. But you should NOT turn on `GSSAPIDelegateCredentials` for arbitrary hosts (make sure you only enable it for HCOOP hosts). Here is an example entry for `~/.ssh/config`: |
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| Host deleuze.hcoop.net ForwardX11Trusted yes |
Host ssh.hcoop.net |
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| User megacz_admin Host mire.hcoop.net ForwardX11Trusted yes GSSAPIAuthentication yes GSSAPIDelegateCredentials yes User megacz_admin |
User fred |
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| == Client side firewall Setting == If you are using a firewall you might want to open it for UDP packets to and from deleuze.hcoop.net:88. Lines for [http://www.netfilter.org/ iptables] saved rules ''might'' look like the following: |
This will allow you to type the following, instead of the longer command above. |
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| [0:0] -A INPUT -s 69.90.123.67 -p udp -m udp --sport 88 --dport 1024:65535 -j ACCEPT | ssh fred@ssh.hcoop.net |
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| = Troubleshooting = Adding "-vvv" to the ssh command line makes it spit out lots of useful debugging information. If you see something like the following in the output: |
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| [0:0] -A OUTPUT -d 69.90.123.67 -p udp -m udp --dport 88 --sport 1024:65535 -j ACCEPT | debug1: Unspecified GSS failure. Minor code may provide more information Server not found in Kerberos database |
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| Put them before any rules that conflicts them (and before 'COMMIT' line in the saved rules file). | check to see if you have an /etc/hosts file with the host that you're trying to reach in it. If there is an entry for this host, make sure that the fully-qualified domain name is listed first, before any aliases that you may be using. == If it still doesn't work == See the [:MemberManual/ShellAccess/TroubleshootingKerberos:Troubleshooting Kerberos] page for more diagnostics. You may also send the output of your ssh command with the "'-vvv'" to hcoop-help and we'll try to figure things out from there. |
This page explains how to log in to our servers without having to type in a password. We use kerberos for this rather than RSA/DSA public keys.
An extra benefit is that passwordless logins using kerberos are noticably faster than passwordless logins using public key authentication. This is because kerberos uses symmetric cryptography (which is faster) and requires fewer round-trips during the authentication process.
Prerequisites
You must have openssh client 4.3 or later. Other versions may work, but we make no guarantees. You will also want the krb5-user package if you are using Debian or Ubuntu. For Mac OS X 10.3 and later no additional software is required for the instructions below to work. For further details, check out ["MemberManual/TransferringFiles/OpenAFS"], and follow just the Kerberos instructions.
Instructions
Once a Kerberos client hsa been installed, you must obtain Kerberos tickets. If your username is "fred", you would do this by typing:
kinit fred@HCOOP.NET
Then type your password when prompted. Note that you must capitalize HCOOP.NET and you must not capitalize your user name. This is important.
Next, make sure you have your tickets. To do this, type
klist
You should see your tickets and their expiration dates.
Last, type
ssh -o 'GSSAPIAuthentication yes' -o 'GSSAPIDelegateCredentials yes' fred@ssh.hcoop.net
(GSSAPI is sort of like Kerberos. Don't worry about the difference at this point.)
Automating things
If you do this a lot, you can include the GSSAPIAuthentication and GSSAPIDelegateCredentials options in your ~/.ssh/config file. But you should NOT turn on GSSAPIDelegateCredentials for arbitrary hosts (make sure you only enable it for HCOOP hosts).
Here is an example entry for ~/.ssh/config:
Host ssh.hcoop.net GSSAPIAuthentication yes GSSAPIDelegateCredentials yes User fred
This will allow you to type the following, instead of the longer command above.
ssh fred@ssh.hcoop.net
Troubleshooting
Adding "-vvv" to the ssh command line makes it spit out lots of useful debugging information.
If you see something like the following in the output:
debug1: Unspecified GSS failure. Minor code may provide more information Server not found in Kerberos database
check to see if you have an /etc/hosts file with the host that you're trying to reach in it. If there is an entry for this host, make sure that the fully-qualified domain name is listed first, before any aliases that you may be using.
If it still doesn't work
See the [:MemberManual/ShellAccess/TroubleshootingKerberos:Troubleshooting Kerberos] page for more diagnostics. You may also send the output of your ssh command with the "'-vvv'" to hcoop-help and we'll try to figure things out from there.