We're trying to develop a newsletter using the build-in newsletter module.

On top of the newsletter there's a table of content. In this table we want to link to the articles in the newsletter using anchors.
So, we've created anchors, and the table of content contains links like: Title

However, when we mail this to ourselves and press the link, we get redirected to www.URL.com/#Article1.

What are we doing wrong, how can we fix this?
This is behaviour that's meant for the website, not for the newsletter, is it?!

Your newsletter must contain full absolute URLs, not relative URLs.

I don't think that i made my point quiet clear. What we want is that we create a newsletter then we will send it to an user. If the user opens the newsletter in his email! he or she will see an area with table of contents and based on anchor point it has to navigate to the article inside the e-mail. NOT on the webpage.

Oh ...

This might not be possible. It will at least depend on the user's email reader, and I'm not sure that will work across everything.

But it isn't possible to make an adjusment in the module that it doesn't turn my relative links into asbolute links?
Because it is possible to work with anchor in e-mail if i send a newsletter without dotnetnuke it works perfectly but dotnetnuke redirect it to the homepage.

You can certainly create the text of your email to have relative links. Check the "source" of the newsletter in the editor to verify that the links are relative.