What is a VPN for, what does it give
VPN creates a connection between one or more computers. This connection uses strong encryption. As a result, you can safely transfer data using unreliable connections. For example, when connecting to an open Wi-Fi network, your traffic is subject to sniffing, both from other devices on the local network, and from those who have not even connected to this network - it is enough to intercept wireless traffic without connecting to it. But if you start using VPN after connecting to an open network, then your traffic is transmitted in encrypted form.
How VPN Works
VPN technology allows you to combine multiple devices into a secure network.
In its work, VPN uses a separation into a server and a client. One server can have multiple clients, which are combined into a virtual private network, where they can exchange data securely.
If some client needs to get access to the global network, then he contacts the VPN server, this server receives data for him and redirects to the requesting client. Because of this work, VPNs are often used to hide IP and bypass blocking.
What is OpenVPN
OpenVPN & ndash; is a free and open source software that implements VPN technology. This program has both a client side and a server side. Works on a variety of operating systems, including Linux and Windows.
Network communication
OpenVPN software transmits data over the network using UDP or TCP using the TUN / TAP driver. UDP and the TUN driver allow clients behind NAT to connect to the OpenVPN server.
You can choose an arbitrary port for OpenVPN, which allows you to overcome the restrictions of the firewall through which access from the local network to the Internet is carried out (if such restrictions are set).
Security and encryption
Security and encryption in OpenVPN is provided by the OpenSSL library and Transport Layer Security (TLS) protocol. Instead of OpenSSL in newer versions of OpenVPN, you can use the PolarSSL library. TLS is an enhancement to Secure Socket Layers (SSL).
Symmetric and asymmetric cryptography can be used in OpenSSL.
In the first case, before starting data transfer, the same secret key must be placed on all network nodes. This raises the problem of securely transmitting this key over an insecure Internet.
In the second case, each participant in the data exchange has two keys & mdash; public (open) and private (secret).
Configuring OpenVPN via http / https proxy
Often you need access to your work computer, which, as a rule, is located behind corporate NAT and can only be accessed through a corporate proxy. In addition, the proxy caused other inconveniences associated with programs that themselves did not know how to work through it.
One day I got sick of it, and prompted me to organize myself remote access through the OpenVPN server, and thus I `` killed two birds with one stone '': organized remote access to a work computer, and a normal Internet on it.
Server Configuration
First of all, you need to enable forwarding. Open /etc/sysctl.conf , change the line or add if not:
net.ipv4.ip_forward = 1
Client Configuration
2 lines must be specified in the client configuration file
http-proxy xxx.mobileproxy.space 64013 auth.txt basichttp-proxy-retry
Where xxx.mobileproxy.space is the address given to you after purchasing a proxy
64013 - your proxy port, always next to the address
auth.txt - file in the root of the program in the format:
loginpassword
with data from a proxy, login and password on a new line