PROXYLIST

 A proxy server (on pp. Proxy - «representative authorized») - Service in computer networks, allowing customers to perform indirect requests to other network services. First, the client connects to the proxy server and requests a resource (eg, e-mail), located on another server. Then the proxy server or connected to that server and receives a life with him, or return the resource from its own cache (if the proxy has a cache). In some cases, request the client or the server's response can be modified proxy server for certain purposes. Also, the proxy server in order to protect the client computer from some network attacks. Using 

Most often proxy servers are used for the following purposes: 
Providing access to the computer network to the Internet. 
Caching data: if the frequent recourse to the same external resources, we can keep a copy on the proxy server and to issue on demand, thus reducing the load on the channel to the external network and accelerate the customer the requested information. 
Data Compression: the proxy server retrieves information from the Internet and transmits information to the end user in a compressed format. These proxy servers are used mainly in order to save external traffic. 
Protecting the LAN from external access: for example, you can configure a proxy server so that the local computer will look to external resources only through him, and external computers will not be able to contact the local at all (they «sees» only the proxy server). See also NAT. 
Restrict access from the LAN to the outside: for example, you can restrict access to certain websites, restrict the use of the Internet in any local users, to establish quotas for traffic, or bandwidth, to filter ads and viruses. 
Anonymization of access to various resources. A proxy server can hide information about the source of the request, or user. In this case the target server only sees the proxy information, for example, IP-address, but has been unable to identify the true source of the request. There are also distorting proxy servers, which transmit the target server with false information about the true user. 

Many proxy servers are used for several purposes simultaneously. Some proxy servers are limited to a few ports: 80 (HTTP), 443 (encrypted connection HTTPS), 20,21 (FTP). 

In contrast to the gateway, a proxy server usually does not pass ICMP-traffic (it is impossible to check the availability of machine commands ping and tracert). 

A proxy server that can access any user of the Internet, is called open.

PROXYLIST