Howto create DNS domain with same name as website domain

[zentomatiker]

hi,

we are running a Zentyal 4.2 server. We created a DNS domain xyz.eu with some hostnames. Everything is working fine, except the access to our website which has also the same domain name xyz.eu. The website is hosted by an external company and is not accessible from within our network. We therefore created a hostname www and assigned the public ip of the webserver (discovered using ping xyz.eu) to the hostname. Now if we type access www.xyz.eu, the website is accessible, but the connection is horribly slow. The website will be loaded partially and images won't be loaded. If we omit the www and type in only xyz.eu the browser reports: "The connection has timed out". If we configure a domain xyz.local everything is fine and the website is accessible.

Any ideas what the problem could be and what I could do to solve the problem?
Thanks.