22.5. Virtual Private Networking
After reading the previous pages, you might assume that it's a piece of cake for business
people to connect to their corporate networks across the Internet from wherever they
happen to be: their homes, hotel rooms, or local Starbucks. But even though the steps on
the preceding pages work fine if you're dialing into your home machine, they'll probably
fail miserably when you want to connect to a corporate network. There's one enormous
obstacle in your way: Internet security.
The typical corporate network is guarded by a team of steely-eyed administrators for
whom Job Number One is preventing access by unauthorized visitors. They perform this
job primarily with the aid of a super-secure firewall that seals off the company's network
from the Internet.
So how can you tap into the network from the road? One solution is to create a hole in the
firewall for each authorized user — software that permits incoming Internet traffic only
from specified IP addresses like your Mac's. Unfortunately, this setup isn't bulletproof,
security-wise. It's also a pain for administrators to manage.
Another solution: You could dial directly into the corporate network, modem-to modem.
That's plenty secure, but it bypasses the Internet, and therefore winds up being expensive.
(Want proof? Try this simple test: Make a call from the Tokyo Hilton to the
Poughkeepsie Sheet Metal home office. Have a look at your hotel bill when you check
out.)
Fortunately, there's a third solution that's both secure and cheap: the Virtual Private
Networke, or VPN. Running a VPN allows you to create a super-secure "tunnel" from
your Mac, across the Internet, and straight into your corporate network. All data passing
through this tunnel is heavily encrypted; to the Internet eavesdropper, it looks like so
much undecipherable gobbledygook.
And it's cheap—whether you're accessing the Internet via your home DSL, a local ISP
number from a hotel, or wirelessly from your stool at Starbucks.
Remember, though, that VPN is a corporate tool, run by corporate nerds. You can't use
this feature without these pieces in place:
•
A VPN server. This is a big deal. If your tech department tells you they don't have

Preferences and fills in the blanks for you. If not, you can do all that manually:
1. Open System Preferences. Click Network. Click the + button below the list of
connections at the left side.
The "Select an interface" sheet appears.
2. From the pop-up menu, choose VPN.
Now a new pop-up menu appears, called VPN Type; you're supposed to choose
either L2TP (Layer 2 Tunneling Protocol) or PPTP (Point to Point Tunneling
Protocol). Find out which system your company's network uses.

Tip: Leopard doesn't work with the third popular type, called IPSec (IP Security).
If your company uses that type, though, you can download Cisco's free IPSec
connection program for Mac OS X from cisco.com.

3. Choose the type of VPN from the VPN Type pop-up menu. Type a name for this
connection (it can be anything you want). Click Create.
You return to the main Network pane, where the settings boxes for your VPN are
waiting (Figure 22-5
).
4. Fill in the server address and account name. Click Authentication Settings to
specify your password and other security settings.
Here, for example, is where you indicate that you have one of those SecurID
cards.
5. Click OK. Turn on "Show VPN Status in menu bar.
That checkbox makes the VPN menulet appear; it's your ticket to getting
connected (Figure 22-5
, top).

Tip: If you always connect to the same VPN, you can turn on the new Leopard feature
called VPN on Demand. It autoconnects you to your corporate VPN every time you
direct your Web browser to a Web site, file server, or resource that requires the VPN


Tip: To connect to a shared folder on a Windows machine, the address looks like this:
smb://111.222.33.4/ sales-docs. Of course, you'd substitute the correct IP address for the
dummy one shown here, and insert the actual name of the shared folder. (You can also
use its DNS name instead of the IP address, if you know it, like this: smb://big-blue-
server.ferret-lan.com/sales-docs.)

When you're finished accessing the remote network, choose Disconnect from the VPN
menulet. (Accessing other Web sites can be slow while you're on a VPN.)
22.5.3. The Fine Points of VPN
For all the wonders of VPN, here are some possible complications:
•
If you're using a router at home (a little box that shares one cable modem or DSL
box with several computers),it might not be able to handle the tunneling protocols,
or it might not have that feature turned on. Check the router's manual, or ask its
manufacturer for more information. For example, the first-generation (silver)
AirPort base stations can't handle VPNs at all.
•
If the corporate network doesn't seem to like your name and password, you might
need to add your NT domain name and a backwards slash to the beginning of your
account name (like this: dom01\msmith) before trying again.
If you're able to make the connection, but experiencing trouble reaching services
by their DNS names (for example, big-blue-server.com), your Mac could be
having difficulty finding the right DNS server. Working with your network
administrator, open the Network pane of System Preferences. Click VPN, then
click Advanced, and then DNS; enter the desired DNS server addresses in the
DNS Servers box. Click OK, then Apply, and then try the VPN connection again.
•
If you're still having problems using the VPN, look at the logs (automatically kept
technical records) for clues to share with your network administrator. To view