SnapGear 1.7.8 manual Virtual Private Networking, 1VPN tunneling using the Pptp server

Page 72

7. Virtual Private Networking

Virtual Private Networking (VPN) enables two or more locations to communicate securely and effectively, usually across a public network (e.g. the Internet) and has the following key traits:

Privacy - no one else can see what you are communicating

Authentication - you know who you are communicating with

Integrity - no one else can tamper with your messages/data

Using VPN, you can access the office network securely across the Internet using Point- to-Point Tunneling Protocol (PPTP) or IPSec. If you take your portable computer on a business trip, you can dial a local number to connect to your Internet access provider and then create a second connection (called a “tunnel”) into your office network across the Internet and have the same access to your corporate network as if you were connected directly from your office. Similarly, telecommuters can also set up a VPN tunnel over their cable modem or DSL links to their local ISP.

With the SnapGear appliance you can establish a secure VPN over the Internet using either PPTP or IPSec. IPSec provides better security; however PPTP is the preferred protocol for integrating with existing Microsoft infrastructure. The SnapGear appliance provides a PPTP server to enable remote Windows clients to securely access your office network. Using the SnapGear appliance’s PPTP client or IPSec you can also connect your office network to one or more remote networks.

This chapter explains how to configure the PPTP server and client, as well as IPSec, in your SnapGear appliance and how to set up remote clients to connect to your VPN tunnel as shown in the following figure:

Figure 7.1VPN tunneling using the PPTP server

69

Virtual Private Networking

Image 72
Contents Rev May 2nd Table of contents Virtual Private Networking Introduction Terminology Term MeaningLAN Document conventions TCP/IPInstalling and configuring your SnapGear appliance Step ChapterYour SnapGear appliance LEDsLabel Activity Description SnapGear appliance back panels Network interconnections SnapGear appliance features Software featuresInternet link features LAN link featuresDial-in connection features Environmental features Static IP reset Getting startedNew Networks 10.0.0.0 10.255.255.255 10/8 prefix192.168.0.0 192.168.0.255 192.168.0/24 prefix Configuring the SnapGear appliance on your network Page Set up IP addresses Your SnapGear appliance was found on the network Multiple SnapGear appliances were found on the networkYour SnapGear appliance needs an IP address Administrative password SnapGear Management Console web administration pagesInitial setup using Linux Using linsetipUsing an existing local Dhcp or Bootp server Ping -b subnet broadcast address Arp -aConfiguring a new local Dhcp or Bootp server Edit the /etc/inetd.conf fileSnapGear Quick Setup LAN port quick setup LAN port quick setupISP connection quick setup ISP connection quick setupGetting started Configuring the PCs on your network TCP/IP properties Connecting to the Internet Physically connect modem deviceSelect Internet connection Connect to Internet cable modemConnect to Internet Adsl Connect to Internet direct Connect to Internet modemISP. The Password and Confirm Password fields must Field DescriptionAdvanced configuration option Internet failoverFollowing figure shows the failover configuration screen Failed connection Configure PCs to use SnapGear appliance Internet gateway Establishing the connectionDial-in server configuration Dial-in server configuration Dial-in setup Dial-in setupField Description Dial-in user accounts Dial-in user account creationFollowing figure shows the user maintenance screen Dial-in password error Account listRemote user configuration For Windows 95 and WindowsServer types Windows Connect to dialogue boxClick Next to continue 11 Connection availability 13 Remote access login screen Network configuration IP configurationNetwork configuration Advanced IP configuration Advanced IP configurationNetwork configuration Dhcp server configuration Dhcp serverNetwork configuration Advanced networking Traffic shapingAdditional routes Incoming access FirewallIncoming access administration services Incoming access configurationExternal access to services Configure external access to servicesPort forwarding configuration Port forwardingOutgoing access Security group classes configurationOutgoing access settings Firewall rulesIntrusion detection and blocking configuration Intrusion detection and blockingPage Content filtering Content filtering Filtering levels and reporting Filtering Level Description1VPN tunneling using the Pptp server Virtual Private NetworkingPptp client setup Pptp client configuration Pptp server setup Enable and configure the Pptp VPN server Pptp server setupField Description Configuring user accounts for VPN server 4PPTP VPN server accounts screenVirtual Private Networking Configuring the remote VPN client VPN Pptp IP addressVirtual Private Networking VPN client setup Windows 95 and WindowsYour VPN client is now set up correctly Windows NT Network and dial-up connections This displays the Destination Address window Connecting the remote VPN client IPSec setup 12 IPSec setup13 Add new IPSec connection Virtual Private Networking 14 Automatic keying setup Aggressive mode phase 1 settings Technique DescriptionIPSec interoperability Password SystemTime server Diagnostics AdvancedFlash upgrade Reset buttonTechnical support Technical supportAppendix a LED status patterns LED Pattern Status ActionAccess Logging Appendix B System LogDefault Deny Eth0Eth1 PppCreating Custom Log Rules Forward Iptables -I Forward -j LOG -i eth+ -o eth+ -p tcp Administrative Access Logging Rate LimitingBoot Log Messages