IIS is returning back computer hostname instead of public ..

Hello.-

I have a Windows 2003 Server with IIS 6.0 on it hosting a site
developed in asp that works internally; I also have a public domain
name Ex. mydomain.com pointing to the server. What is happening is
that when I use externally mydomain.com/application, it prompts me for
my server login and password as it does internally but then I received
an error "the page cannot be displayed" but also when I get the error
I noticed that my URL changes from mydomain.com/application to
myservername/application.

I believe my site is not displaying because IIS is returning
myservername/application instead of mydomain.com/application. I
believe it does the same thing internally, but works because
internally the DNS can resolved the computer name while outside it
can't.

It might be an easy fix, but is not coming back to me right now.

Any help on this will be really appreciated.

Thanks

Thanks Ken for your prompt reply. This is driving me crazy, I will try
to find out what the problem is. I don't have any extra application or
anything that could do this, so I guess it could be down to DNS, ASP
programming or something like that. If you think of something else
please let me know.

Thanks