PROXY SERVER COMMUNICATION

[avilt]

I need some clarification on Proxy Server. When you configure internet browser like IE or Firefox to use Proxy server for communication (for all the protocols includng HTTP/FTP/GOPHER etc) does it uses the same port for all the communication? If so is it possible to restrict network access at the proxy server? Lets say I want some users to have only web access and some FTP. Is it possible with this kind of setup?

Thanks

[Farrukh Haroon · Accepted solution]

All traffic between the clients >> proxy server in on the proxy server port. Then the Proxy server 'sources'/proxies a 'new' connection having its IP as the source and the ultimate destination. Of course there are different types of proxy servers also anonymous, transparent etc. but this is the normal behavior. But almost all proxy servers allow you to control which use can access which protocols e.g. MS ISA. This can be done on the basis of username/IP/Machine etc.

Regards

Farrukh

[avilt]

what about FTP communication when set to pass thru proxy? does that happen over http? Is it a passive/active ftp?

[Farrukh Haroon]

FTP goes through as FTP only...no HTTP at all.

Which type FTP is allowed by default depends on each individual proxy server (ISA,Squid,BlueCoat etc.). If its not allowed by default than special handling needs to be done. For example on Microsoft ISA, you have to make some rules to allow both types of FTP.

There is no 'general rule' here. You really have to test it out or refer to the documentation of the proxy vendor.

Regards

Farrukh

[avilt]

When you say all the communication between the proxy and the client happens on proxy port then FTP between the client and the proxy server happens over http right? In my Internet Explorer settings LAN connections I have set use Proxy on port 8080 for all the protocols. That means for all including FTP happens on port 8080 right?

[Farrukh Haroon]

As I said before, that all depends on the proxy itself. Just consider the MS ISA server, it operators in various modes and this influences how the proxy behaves. If its a 'HTTP' based proxy, then yes all requests from client >> proxy would be HTTP. You have to be more specific here :).

Regards

Farrukh