Wirtualna Sieć Prywatna

W artykule przedstawiono technologie wirtualnych sieci prywatnych (VPN) na przykładzie oprogramowania OpenVPN. Opisano instalację, konfigurację serwera VPN zaimplementowanego na linuksowym routerze oraz klientów pod systemem operacyjnym Windows. Opisano aspekty związane z bezpieczeństwem przesyłania otwartym kanałem zaszyfrowanych informacji i zasady działania protokołu SSL.

The technologies of virtual private nets (VPN) enabling the safe access to supplies and corporate applications from home unprotected internet nets on the example of software OpenVPN that are based on the open (GPL) General Public License are presented in the paper. In Section 2 there are described both the principle of SSL protocol and the theoretical bases of coding the symmetrical and asymmetrical connection called the mixed coding. The Diffiego-Hellman's algorithm is also introduced. It is responsible for save distribution of private keys by an open channel. There is presented the mechanism called a reliable institution of the keys storage - certificate authenticity. Section 3 is concentrated on the practical use of the technology called VPN. It presents the installation of free software - OpenVPN. Further on, the way of generating keys and certificates is introduced as well as the server and clients' configuration. The VPN server role is functioned by Linksys WRT54GL router where the original firmware is replaced by an alternative firmware called dd-wrt.v24_vpn. However, the VPN client works under the control of the Windows system. Finally, the topology of VPN net (tunnels) based on real distracted net is described.