How get referring URL?

[eluser]Xeoncross[/eluser]
[quote author="einstein" date="1218056774"]As far as i know the session can handle only a few kb / session.[/quote]

If you use the recommended method of a storing session data in a system file or DB - then this doesn't matter.

Also, storing something like this in a config file is a really bad idea - not only will each person that requests the page get overwrite the last value - but users will get other users redirect values. It also will take a lot of overhead to do something that could be done with sessions so easy.