AhmetNuri
But I don't konw which is best way for transparent proxy.
There is no best way.
You use the auth login method that your situation requires ie if you must authenticate against users on sme server, then you have to use pam auth, you have no other choice, and in that case you need to disable transparent proxy for pam auth to work OK.
If you are happy to maintain seperate user lists then you can use ncsa auth.
If you prefer to use ident auth then you need an ident client software on your workstations.
The reasons for using each vary.
There is no mention of disabling Transparent proxy for ncsa or ident auth in the Howto, so if you feel you must use a Transparent proxy then you are limited to using one of those auth methods.