How to Build an Ubuntu 11.10 SBS (Small Business Server)

This guide will help you configure Ubuntu Server Edition 11.10 for a small/medium business. The server will provide DHCP, DNS, NTP, LDAP, Kerberos and NFS services such that users can login to any machine on the network and all their files and settings will be the same across the entire network.
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How To Generate An SSH Keypair To Allow Password-less Logins

It’s quite common to use SSH/SCP in scripts, particularly for backup purposes. Unfortunately, this would mean storing a password in the script, which would consequently appear in logs etc… A much better plan is to use SSH keypairs. Once you’ve created a passphrase-less keypair and copied it to both machines, you can login without a password.

Firstly we’ll create the key on the client machine. This is the machine that you want to be able to connect FROM without using a password. In this scenario, the machine “www” is going to run a backup script that needs to store data on “neo” without using a password. So we create the key on “www”.

ssh-keygen -t rsa -b 4096

The -b 4096 is optional, but will instruct the machine to generate a more secure 4096bit key rather than the default 2048 bit one.

When asked for a passphrase, simply hit enter for none.

Now we need to copy the key to the machine that we want to be able to access without a password:

ssh-copy-id -i ~/.ssh/id_rsa.pub dan@neo.danbishop.org

You will be prompted for your password for the user dan@neo.danbishop.org.

All done 🙂

You can now type “ssh neo” and it will log you straight in without asking for your password! 😀