VPN Information
Summary: Information about using why you would want to use VPN, who can benefit from it, where it can be used from and the different types of "tunnels".
Why use a VPN?
Network Traffic Encryption
When you connect to another site using a VPN, your traffic is encrypted so
that if anyone intercepts the traffic, they cannot see what you are doing
unless they can break the encryption. Your traffic is encrypted from
your computer through the network to the VPN concentrator hardware at UCI. At
that point the traffic is un-encrypted and sent out over the campus network. If
you are using software like ssh,
your traffic on the campus network is still encrypted because ssh encrypts
its traffic.
Access UCI Resources
When you are using a VPN connection, it will appear to systems on campus that
you are also on campus - you will have a UCI IP address instead of the
one you have at home (Cox, AT&T, PacBell, etc). This allows you
to connect to resources that you would not be able to from home, and bypass
any port blocking at the campus border router.
Windows File Shares
The VPN offers a way for authorized users to mount Microsoft Windows file shares
from off campus. As of November 5th, 2002, a VPN is required
to use "shares" from outside of UCInet because of special
port blockades.
Who Needs VPN?
You need VPN if:
- You mount a Windows disk share from your work computer on your home computer.
- You need to access restricted services.
- You use network protocols like NetBIOS to a host or service on campus.
- You are using a public network, (for example, in a hotel, coffee shop, or airport), especially if it is a wireless network.
You don't need VPN if:
- You check your UCI e-mail via IMAP with SSL/STARTTLS encryption.
Downsides to using VPN if it is not needed.
- Slows down your connection
- Uses resources others could be using
- Adds a step to connect to UCI
Where Can I Use VPN From?
VPN service can be connected from any off-campus Internet location or UCInet Mobile Access (wireless) network. It will not work from the campus dial-in modems or any host on campus.
VPN Tunnels
UCI has two types of VPN tunnels, a "split" tunnel and a "full" tunnel.
Split Tunnel
The "split" tunnel only sends traffic destined for UCI over
the VPN connection. All other traffic goes through your normal cable
modem/dsl connection. Use the "split" tunnel for
connections to and from UCI only. If you are using online Library resources,
use the "full" tunnel.
It allows you to talk directly to the Internet, but when your machine "talks" to UCI network addresses the traffic is put through the established VPN tunnel to the UCI VPN node, where it is decrypted and given a UCInet network address.
This is useful for people who need access to things at UCI which require a UCInet IP address (such as connecting to a system that restricts access to UCI hosts only), or to use services which are blocked for security reasons at the campus firewall (such as NetBIOS ports, used in mounting shared drives and other ports used by Microsoft Windows). Only traffic to/from UCI is sent through the VPN connection, so if you were to access Yahoo, it would go through your regular network connection (cable modem, dsl, etc).
Full Tunnel
The "full" tunnel sends all your internet traffic
through the VPN connection, and then out to the internet through UCI's
connection.
The "full" tunnel is useful for people who need to access sites off-campus that need a UCI IP address to allow access to a resource. The UCI Library has links to resources such as these. If you wanted to access the Oxford English Dictionary (OED), you can't get to it with a split tunnel because it's off campus and your off-campus packets aren't network address translated to UCI addresses. By using the "full" tunnel, this problem is circumvented. However, note that *all* your traffic is sent through the VPN connection and then out UCI's internet connection.
You should use the "full" tunnel VPN connection with care since heavy use can cause an increase in UCI's internet connection costs, and is likely slower than the split tunnel method.
Timeouts and Limitations
Timeouts
Once you bring up your VPN client and initiate a connection, you will
remain connected as long as you're actively using it. If the connection
is idle for one hour, it will "timeout". If
you are not going to use your computer, it is best to take down the connection
yourself, to free-up a tunnel for someone else to use. In either case,
when you later come back to your computer you will need to re-initiate
a connection if you still need to use the VPN.
Limitations
There is a limit of 2 VPN tunnels which may be simultaneously
established under one UCInetID.
The campus VPN provides off-campus users access to university resources not normally available to remote users and is thus a critical resource. The VPN appliance handles connections for all users through the same 100 Mb interface. Users of bandwidth-intensive applications that are not related to the University's academic mission can detrimentally impact other users on the VPN.
For this reason, Gnutella, Kazaa, Bit Torrent, E-Donkey, and other peer to peer (p2p) file sharing programs (as well as internet gaming and other recreational, high-bandwidth applications) are not allowed on the VPN.
VPN Addresses
For those of you who would like to allow or restrict access from VPN users, here are the possible address ranges that VPN users will be using.169.234.240.100 - 169.234.255.254
