How to discover Subdomain from our website? / How to connect without IP

I was now deploying my webservice. I developed a android java client where I have to use URLs with IPs. The problem is, I don't know the s开发者_运维知识库ubdomain. For example:

private static final String URL = "http://apkitchen.voku-online.de/something.php";

It's easy to convert that url to an IP (it's also the same as FTP use) but the problem is when I enter that IP on the browser I go to other website on that domain because I have to know the alias.

- http://81.x.x.x/subDomain/OTHER_ALIAS_MAYBE/My_files

There's any way to discover the alias, subdomain (i dont really know the right technical term in english, sorry).

Alternatively if there's a way to connect without IP, I would like to know.

Thanks in advance.

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For those who are in same position, it's not possible unless you own the server or contacting the owner/manager.