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I have a very hard time setting up owncloud so that i can use it with ip adresses. Even gives me an error.
the only way that works is by using a domain instead of ip, but i really need to use the ip.
even adding them to config.php doesn't work....

Depends a bit how you configured your webserver's virtual hosts. Normally the first VirtualHost is used in Apache if none of the others match (with ServerName). More on this with a number of examples: