Authenticaion in Squid Transparent Proxy, not possible ?

[cyberkoa]

I have just set up a Squid Proxy running in transparent mode followed the guide from Ricky (thanks!)

The server works as proxy and router at the same time.

I need to control the the Internet usage, therefore I need to let the user to be prompt a user ID and password before using the Internet.

I have tried to search in google and squid website, the conclusion is Squid in transparent mode cannot implement authentication simply by changing the squid setting.

If cannot , since I need to allow the connection of yahoo, skype , oe , and a AS400 connection then only I use the transparent mode.
My  question is
1. can I implement authentication in transparent mode ?
If not
2. can I implement authentication in normal mode but allow the connection of yahoo messenger , skype , oe and AS400 , FTP connection ?

or other way that can help.

Thanks.

[Ricky]

You can't have authentication in transparent way.. although in begining it will look like working but, it cause errors. So No!

well. in simple proxy you can have authentication but to open yahoo etc.. user first have to be authenticate through browser..

[cyberkoa]

Thanks ricky .

If let say I need to configure in such a way

1. Allow connection of yahoo, Outlook Express  and external FTP without authentication
2. All the others need authentication

Since I need authentication , I will need to configure a simple squid proxy .

Can Squid make it ?
Before I set up a transparant proxy , I use a simple proxy but the user can only surf web but not all the others ., what is the trick in the squid.conf need to modify in order to have simple proxy but yahoo , OE and external FTP can run?

[Ricky]

You can either authenticate all or none !

One thing came in mind , that install nat but don't use it for port 80 ! ie use squid for port 80 after authentication.. but that is not seems to be final solution as yahoo messenger also uses port  80 !