two domains pointing to same site

does anyone know how exactly google deals with it

[Dalmatian]

I was lurking your threads for a while and learned that this situation can cause me some problems with Google.
However, I decided to start this topic again, as none of the posts was simillar enough to my exact situation.
My site was started as hobby and evolved into commercial operation so this is my third time changing URL's.

Currently, I have two domains pointing to same content, and it's done by DNS entry at my service provider. Google indexes my "old" domain, and I have PR of 4 which is not bad comparing to my competitors. I submited my new domain to both google and DMOZ months ago, and it shows up in DMOZ but not in Google directory nor Google results.
However, my "new" domain shows grey PR mark in toolbar, and also, no results show up as indexed in Google.
But, regardless of that, same subdirectory at both domains as www.olddomain.com/subdir shows same PR ranking as www.newdomain.com/subdir regardless of not showing up in google results.

My question is simple - in your opinion - what should I do?

[heini]

Hello Dalmatien, welcome to the board.

If I understand that right, the two domains currently active do point to the same content, i.e. you have one site under two names.
If so you should simply make 301 redirects from the old url to the new. That tells the engines the content is under the new site, which then eventually should replace all listings with the old name in the index.

[Dalmatian]

Yes, you got me right.
I now learned that guideline even out of google's faq.
However, by your experience, what's the reason the google is behaving as is with my new domain. Is there any chance it's "punished" or so. Because with removing the content from all listing they would loose their position in search, and if the new one is "punished" or so I would be left without any entries for at least a while.

[NFFC]

>what's the reason the google is behaving as is with my new domain

You have confused them, make it a no-brainer and 301 from the old site to the new. They get that right almost all the time.