1. Virtual Private Networks
Alberto Pace

2. What is a VPN ?
A technology that allows to send confidential data securely over the internet

3. What is a VPN ?
The remote computer can connect to the internet using an arbitrary Internet Service Provider (ISP) and have an IP Address in the intranet.
The computer can act as if it was on the intranet

4. Point-to-Point Tunneling Protocol
You can access a private network through the Internet or other public network by using a virtual private network (VPN) connection with the Point-to-Point Tunneling Protocol (PPTP).
Developed as an extension of the Point-to-Point Protocol (PPP),
PPTP tunnels or encapsulates, IP, IPX, or NetBEUI protocols inside of PPP datagrams
PPTP does not require a dial-up connection. It does, however, require IP connectivity between your computer and the server
My understanding is that it uses Microsoft Point-to-Point Encryption (MPPE)

5. Layer Two Tunneling Protocol
L2TP is an industry-standard Internet tunneling protocol with roughly the same functionality as the Point-to-Point Tunneling Protocol (PPTP).
Like PPTP, L2TP encapsulates Point-to-Point Protocol (PPP) frames, which in turn encapsulate IP, IPX, or NetBEUI protocols
With L2TP, the computer performs all security checks and validations, and enables data encryption, which makes it much safer to send information over nonsecure networks by using the new Internet Protocol security (IPSec)
In this case data transfer through a L2TP-enabled VPN is as secure as within a single LAN at a corporate site

6. Internet Protocol security (IPSec)
IPSec provides machine-level authentication, as well as data encryption.
IPSec negotiates between your computer and its remote tunnel server before an L2TP connection is established, which secures both passwords and data

7. Authentication Methods
Challenge Handshake Authentication Protocol (CHAP)
Uses Message Digest 5 (MD5) / challenge-response
MS-CHAP
Same as Chap + functionality to which LAN-based users are accustomed
MS-CHAP is consistent with standard CHAP (superset of functionalities)
You must at least use MS-CHAP to use MPPE (encryption)
MS-CHAP v2
both the client and the server prove their identities. Not only the client. V2 ensures that you can configure a your connection can be configured to connect to the expected server
Extensible Authentication Protocol (EAP)
Allows to use other security devices. EAP provides a standard mechanism for support of additional authentication methods within PPP including token cards, one-time passwords, public key authentication using smart cards, certificates, and others

8. Types of VPNs
Router-to-Router

9. Types of VPNs
Remote Access VPNs

10. Tests at CERN
PCAP7 (computer in my office)

11. From the client
The machine we have in on the intranet only. We have to simulate internet/intranet.
The page considers intranet the address xxx

12. Connect to the VPN
From “My Network Places” – Right-Click – “Properties” – “Create New Connection”

13. Try to connect

14. Conclusions so far
If we open the pptp port on address , we have today a working solution with the following limitations
Uses PPTP and Microsoft Point-to-Point Encryption
Windows computer have all necessary software natively
Windows Machines can be identified (as member of the domain or an ad-hoc domain)
Security is strengthened by domain logon that can be tightened to anything you want
This is the current “industry standard”
Used world-wide, secure and proven technology
Evolution towards L2TP and IPSec coming, but slowly (requires heavy infrastructure)

15. More conclusion so far
Using this technology, we could open rapidly a VPN service for WINDOWS users
Time to install and configure the VPN server ~ 8 hours
Time to install a windows client that has already TCP/IP connectivity ~ 1 minute
Support for Linux users could come for the “community”
May be very expensive to formally support Linux clients
Not a standard technology – to my knowledge, no companies have “roaming linux users” on the internet to the same extent that we have
Deploying the IPsec infrastructure to support L2TP will require an administrative office to distribute, revoke and maintain computer certificates and user certificates.
May not be possible within the current resources / May require several years
Yet another computer Registration ? Yet another user Registration ?
Should try to have LANDB and CCDB moving in this direction. Only if this happens the investment can be justified.