The Web Proxy serviceprovides Internet access for CERN compliant Web browsers such as Netscape, IE, Opera, ets. It gives multiple computers the ability to use a single IP address. It provides caching* data encripton (using the SSL Secure Sockets Layers). It acts both as a client*, making requests to servers on the Internet and as a server*, fulfiling requests. Most Web communication, be it WWW, FTP,Gopher, use the HTTP protocol as its transport. As its most protocols, HTTP has a specific set of commands, but the 2 most used are GET and POST. The GET command requests the doc specified in the URL, while the POSTis used by the serve to foward the information requested by GET.
The Web proxy service uses 2 applications within the Application Programming Interface (ISAPI)- the filter interface and the application interface. the proxy servwer ISAPI filter and app perform spevific functions in the real of proxy services. Other ISAPI filters or apps can be created and given certain circumstances. The ISAPI filter(located in W3PROXY.dll on the server) examines each request to see if it is a standard HTTP or a CERN proxy request.
Now, what exactly is WinSock? All you losers running Windoze have it. It is a system mechanism for interproccess communnications, and the commmunications can be between diff computers on a LAN(Local Area Network) or a WAN(Wide Area Network).
The concept of sockets is straightforward: To send a message to a machine is not enough - you need to be able to send the message to a specific oftware process, an end point for the communication. By giving each service process running on a machine a "port" - a numeric value used to identify the to process - a client application can distinguish between, say, a file transfer service and a Web service.
The Internet Assigned Numbers Authority value for a given service. For example, Web servers, by default, use TCP connections on Port 80. FTP servers are a little more complex, using TCP on Port 21 for commands and Port 20 for data transfers. Protocols such as echo (Port 7) use UDP or TCP, while SNMP (which uses Port 161) only uses UDP. Most services can be allocated to different port numbers if required. For example, a Web site Instant might run a second Web server on Port f 8080. It is the combination of a port and an IP address that makes a socket. Each improvements client application has a unique socket associated with it, while the socket for a service process may support multiple instances of a service.For example, a Web server might receive a number of service requests on Port 80 in a short period. Instead of handling e requests on a first-in, first-out basis, the server could launch a copy of itself for each request. Knowing the Enterprise client's socket allows the results of each request to be returned to the correct client.
This strategy ensures that service requests that take a long time to complete (for example, having a Web server-based application perform a database lookup) don't block other requests that can be satisfied quicker (such as simple Web content retrievals). The socket API, while simple, is not particularly elegant, and programmers technologies? usually access TCP/IP communications through higher-level APIs, such as Remote Procedure Calls. Under Windows, of course, things are different, and there's a variant of the quick survey. Berkeley Sockets Interface specifically for Windows called, not too surprisingly, the Windows Socket Specification (WinSock).
Currently, most of the Windows market uses the WinSock 1.1 implementation, but Microsoft is slowly but surely moving the market toward WinSock 2, described by some as WinSock 1.1 on steroids. The bottom line is that due to the rise of the Internet and TCP/IP, sockets are now the dominant communications mechanism and look likely to remain in that position for a long time to come.
3.Proxy chaining is primarily supported by DeleGate servers, WinGates, and CGI proxies.DeleGate is a free proxying software that can be found out http://wall.etl.go.jp/delegate/. Common proxy portals that use the DeleGate server software include Magusnet and Spaceproxy. There are many other manual proxies that are DeleGate servers. A DeleGate server would chain to Altavista like this: http://128.11.219.251:8084/-_-http://www.altavista.com/ Notice the colon, identified port number, and chain sign -_- WinGate is also a third-party server software and can be found at http://wingate.deerfield.com/. The 2.0 versions had default settings that allowed anyone to "bounce off" of the server and had logging turned off. It allowed not just the http protocol to be proxied through but more usefully telnet and ftp could be used as well. WinGate is now at version 4.0 and has tightened up security considerably so these "open servers" are exceedingly rare now. Many CGI proxies are derived from the original script written James Marshall. It can be found at http://www.jmarshall.com/tools/cgiproxy/. The people at Cyberarmy have a simplified version of the J. Marshall script called the CyberAnonymizer that has been widely distributed. The Australian Whois.com.au/ uses the CyberAnonymizer. Other CGI proxies include Anonymizer and other common web-interface proxies many people are more familiar with. Each class of proxy has its own chain syntax convention. Some web-interface proxies chain like this: http://invis.free.anonymizer.com/http://www.altavista.com/ Some CGI proxies chain by adding cgi paths to the URL like this: http://isecure.dreamhost.com/nph-a2.cgi/http/www.altavista.com |
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some experiments that you may find helpfull. I entered '127.0.0.1:8080' into the 'manual proxy' field and tried to reach as url 'http://mysite.com/index.htm' here is what my netscape actually send :
Now if I enter as url the following : http://myproxy.com:8080/mysite.com/index.htm I get :
As you can see, The Host header do well include the :8080 So, to summarize, I think the problem origin may be your second guess which is confirmed by NME : It depend on how proxies must be chained together. It should maybe be usefull to find out some 'syntax' on how web proxies should be used ... |