Note We assume you haven t generated an SSH key yet. in Font

Generation QR Code in Font Note We assume you haven t generated an SSH key yet.

First you need to make a key pair. To do this, you will use DSA as the key type to ensure that you will be connecting via the more secure SSH2 protocol: ssh-keygen -t dsa You will be prompted for a filename; press Return to accept the default. You will then be prompted for a key passphrase. If you want it to prompt for a passphrase, enter it now; otherwise, for unchallenged logins, hit Return to set it to blank. Now you will have your new public-private key set in ~/.ssh. The private key is named id_dsa, and the public is id_dsa.pub. For the server to use the key, you must copy your public key to it. If keys have not been used for authentication up to this point, you can simply copy the key to the remote host and rename it: scp ~/.ssh/id_dsa.pub user@host:~/.ssh/authorized_keys This will create or replace your authorized keys file on the server. If you have authorized keys already, you should add to the file like so: cat ~/.ssh/id_dsa.pub | ssh user@host 'cat - >> ~/.ssh/authorized_keys' Now try logging into the SSH server as you would normally: ssh host.domain.com -l username If you specified a passphrase, you will be asked for it; otherwise, it will automatically grant you access.

When using keysets without passphrases, it is imperative that the key not fall into the wrong hands. If a compromised passphrase is suspected, it should be destroyed immediately and a new one should be generated right away.

A virtual private network (VPN) is a private communications tunnel, established within a public network, between two points, one inside a network and one outside of it. Safe communication through this tunnel is possible through encrypted network traffic.

Many companies will have a VPN in place that you can use to connect to the office. When you use the VPN to connect to your office, then you are using a public network (that is, the Internet) to establish a private network (the VPN tunnel). Once you have a private network, then you will likely be able to access many of the resources just as you would if you were in the office, only a little slower because you are working from the LAN.

If you are going to set up a VPN client, then you first need to obtain configuration settings from your office. First, you need to know what VPN protocol your network is using. The two main types of VPNs are PPTP and L2TP over IPSec. Once you know the type of VPN you are connecting to, then you will need to know the address of the VPN server. This is often an IP address or a DNS name. To start, open the Network preference pane, and click the plus sign to open the Select the Interface screen. At the Select the Interface screen, choose VPN as the interface, and then choose appropriate VPN type (PPTP or L2TP) for your environment. Once you have entered this information, click the Create button (see Figure 12-14).

If you will be connecting to a PPTP-based VPN, then you will also need to know the username and password to connect with this connection. Once you have this information, you will be able to configure the VPN. Once you have a connection created and you have obtained the correct address, account, and password, then you can complete the setup. To do so, open the Network preference pane, and click the PPTP connection you created earlier. Then enter the username in the Account Name field (see Figure 12-15) and the address of the VPN server in the Server Address field. If you have another authentication method other than simple password authentication required to establish a connection, click the Advanced button. At the User Authentication screen (see Figure 12-16), select your authentication type, and click OK. Once you are finished configuring all the required settings, click Apply in the Network preference pane, and test your connection by clicking the Connect button.

Tip To make connecting easier, select the Show VPN Status check box in Connection Settings. This will

put an icon in the menu bar that allows you to quickly connect to any of the VPN connections you have set up.