What Is The Circuit Level Proxy?

generic proxy

Circuit Level Proxy Or The Generic Proxy

A circuit-level proxy (also known as a generic proxy) is a packet filter module that can be used to block or enable any IP address and port on a firewall without, however, being able to analyze the contents of the packet.

Such a proxy, operating on OSI layers 3 and 4, sometimes simply passes the packets without terminating the connections themselves. The Circuit Level Proxy then implements the address translation using NAT on the OSI layer 3. While the address filtering is also based on the third OSI layer, it also implements a port filtering on the fourth OSI layer.

There are also Circuit Level Proxies, which can realize an authentication on the OSI layer 5 thanks to a special protocol. The client gets such a connection approval z. B. by entering an identifier and password. However, the client must be aware of this special authentication protocol, which is why such an enabled Circuit Level Proxy is less generic (it only works with applications on the client that have been extended accordingly).

As an example of such an authentication protocol is SOCKS called. Such an extended Circuit Level Proxy does not necessarily rely on NAT. Some of them even make this dependent on the protocol; so z. For example, the TCP connection is terminated while a UDP connection is simply passed.

A generic proxy site can also be used for easy forwarding. The simplest possible proxy is the Linux program Redir, which listens on one interface and one port and forwards the data to another interface and port. This is also possible with the iptables command under Linux and is used, for example, to route the exit traffic of a Tor server across several proxies in order to protect the Tor server.

What Are The Main Features Of HTTP?

what is http

What Is TCT/IP Protocol?

  • HTTP is built on the TCP / IP protocol and the default port number is 80
  • HTTP is a connectionless stateless of
  • HTTP packets
  • Request message

The HTTP protocol is transmitted in ASCII code and establishes an application layer specification over the TCP / IP protocol. The specification divides the HTTP request into three parts: the status line, the request header, and the message body. Similar to the following:

<method> <request-URL> <version>


HTTP defines different ways to interact with the server, there are four basic methods, namely GET, POST, PUT, and DELETE. Add, change, delete, and delete operations on the network, and the HTTP GET, POST, PUT, and DELETE on operations.

1.GET is used for information acquisition and should be safe and idempotent.

The so-called safe means that the operation is used to obtain information instead of modifying information. In other words, GET requests should not generally produce side effects. That is to say, it will only obtain obtainable resource information, just like a database query, it will not be modified, add data, will not affect the state of the resource can get by proxysite.

Impotence means that multiple requests to the same URL should return the same result.

Example of a GET request message:

 GET / books /? Sex = man & name = Professional HTTP / 1.1

 Host: www.example.com

 User-Agent: Mozilla / 5.0 (Windows; U; Windows NT 5.1; en-US; rv: 1.7.6)

 Gecko / 20050225 Firefox / 1.0.1

 Connection: Keep-Alive

  1. The POST indicates that the request to change resources on the server may be modified.
  2. POST / HTTP / 1.1
  3. Host: www.example.com
  4. User-Agent: Mozilla / 5.0 (Windows; Windows NT 5.1; en-US; rv: 1.7.6)
  5. Gecko / 20050225 Firefox / 1.0.1
  6. Content-Type: application / x-www-form-urlencoded
  7. Content-Length: 40
  8. Connection: Keep-Alive
  9. Sex = man & name = Professional
  10. Note:

The amount of data that GET can submit is limited by the length of the URL, and the HTTP protocol specification does not restrict the length of the URL. This limit is limited by the specific browser and server

Theoretically speaking, POST is not limited in size, and the HTTP protocol specification has no size limit. For security reasons, server software will impose certain restrictions when it is implemented.

Contribution To Cybersecurity Through Proxysite


Contribution to cybersecurity

It contributes a lot to network security, such as the anti-intelligence fraud alliance, the Safe Wi-Fi Alliance, and anti-virus labs that have been established in recent years.

In particular, the Secure Wi-Fi Alliance has made up for the flaws and vacancies in security software for Wi-Fi protection on the market. Its anti-virus capability has also been greatly improved Proxysite.

Tencent Computer Butler’s engine TAV engine is created by the anti-virus laboratory and is more suitable for the domestic network environment. For many viruses, the exclusive killing can be achieved

As much as possible. Suggest that you can pay attention to this activity of cybersecurity week, many companies including penguins will participate in the

The Biggest Contribution To Network Security Is Free To Upgrade Win10

Netease Technology News November 18, according to foreign media reports, Microsoft CEO Satya Nadella on Tuesday described to the public the company’s bold measures to protect the safety of Windows users. However, Microsoft’s greatest contribution to network security is a free upgrade to Windows 10.

“The network security situation was quite severe in 2015,” said Nadella at the annual meeting of the Microsoft Government Cloud Forum in Washington, DC. “The most serious 8 or 9 data breaches have endangered the safety of 160 million data records,” and the global economy has lost more than $30 trillion.

Adoption Of Hope

When talking about the company’s countermeasures, It is pointed out that Microsoft will create a “Network Defense Action Center” internally to analyze possible threats and coordinate the company’s countermeasures. Microsoft has set up a corporate network security division to provide threat assessment and monitoring services.

Regardless of whether these practices are effective, the key to cybersecurity for most consumers is to install the latest version of the new operating system, which does not necessarily take time or money.

That’s Microsoft introduced a free upgrade system this year. It spares no effort to turn Windows from a product to a service. Upgrade patches are also included in this new program and will be automatically installed in the background.

Although free, there are still quite a few users who are not using the latest Windows system. According to Microsoft’s statistics, about 1.5 billion people use Windows in the world, but only 110 million of them have upgraded to the latest Win 10

How The Proxy Server Works

proxy server

Proxy also known as network allows a network terminal (typically clients) via this service with another network terminal (normally a server) non-direct connection.

Some gateways, routers and other network equipment with network proxy site. Agency services are generally believed to help protect the privacy or security of network terminals and prevent attacks.

Agency services computer systems or other types of network terminal called proxy server.

A complete proxy request process is as follows: The client first establishes a connection with the proxy server, and then requests to establish a connection to the target server or obtain the specified resource (for example, a file) of the agent, is a special kind of network service that target server according to the proxy protocol used by the proxy server.

In the latter case, the proxy server may download the resource of the target server to the local cache.

If the client wants to obtain the resource in the proxy server’s cache, the proxy server does not want to send the request to the target server but directly return cached resources.

What Is Proxy Protocol?

proxy server and firewall

Some proxy protocols allow the proxy server to change the client’s original request to the original server to satisfy the needs of the proxy protocol.

Proxy server options and settings in a computer program typically include a “firewall” that allows the user to enter the proxy address, which covers their network activity and allows filtering across the Internet for network access.

Function of The Proxy Server

  1. Increase the speed of access: usually the proxy server is set to a larger buffer, when the outside information is passed, but also to save it to the buffer, when other users access the same information, then directly from the buffer remove the information, passed to the user, in order to improve access speed.
  2. Control access to internal resources: If a university FTP (provided that the proxy address within the allowable access to the resources), the use of educational network address free proxy server, you can use for educational network open all kinds of FTP Download and upload, as well as various types of information sharing and other services.
  3. Filtering content: for example, limiting access to specific computers, translating data from one language to another, or defending offensive access to both sides of a proxy server.
  4. Hide real IP: Internet users can hide their own IP through the proxy server, from attack. However, it is only one agent to guarantee safety. A safer method is to use a specific tool to set up an agent chain (e.g. Tor).
  5. Break their own IP access restrictions: visit foreign sites. China Education Network and 169 network users search as Internet users can visit foreign websites.
  6. Break through the content filtering mechanism to restrict access to filtered sites. Restrictions on internet access in China search the browser.

But every time the National Day, the two sessions and other sensitive period, the Great Firewall of the firewall wants to improve the blockade, most of the proxy server and proxy software will not be able to connect. (Such as: gate, free door, unbounded browsing, etc.)