Forwarding from subdomain to port not working - apache

Question

the problem:
I am running a Windows Vserver and on this server I'm running a standalone Grails app on port 8081, which means that when I open
localhost:8081 (local) or domain:8081
in the browser, I see the interface of the Grails app.
What I am looking for is a way to type
subdomain.domain
that forwards me to
domain:port
I have read that this can be done using a virtual host on Apache. I used the XAMPP Apache because I'm running XAMPP MySQL anyway.
I added this line to the WIndows host file:
127.0.0.1 subdomain.domain
and this part to apache/conf/extra/httpd-vhosts.conf:
<VirtualHost *:80>
ServerName http://localhost
DocumentRoot "C:/xampp/htdocs"
</VirtualHost>
<VirtualHost *:80>
ServerName http://subdomain.localhost
Redirect / http://localhost:8081
</VirtualHost>
What I expected:
when I open domain I see the xampp admin interface
when I open subdomain.domain I see the Grails app (as domain:port)
What happens:
no matter wheather I open domain oder subdomain.domain I'm always forwarded to domain:port
What am I doing wrong?
Regards
H

Answer 1

Solution (no idea where the technical difference is):
<VirtualHost Server-IP:80>
ServerName http://domain
DocumentRoot "C:/xampp/htdocs"
</VirtualHost>
<VirtualHost Server-IP:80>
ServerName http://subdomain.domain
Redirect / http://domain:port
</VirtualHost>
I even didn't have to make any entries in the Windows host file. NameVirtualHost wasn't necessary either.