Which Ports for DCOM

Hello,
there are some discussions in our company to allow developers access for DCOM Communication.
So we have to open our firewall. But I can't find informations about the port range we have to open.
I've found one article that DCOM Communication will not function with a networkaccess over NAT.
So my questions are:
-Will DCOM work with NetworkAdressTranslation
-Which Port/Range I have to open
-There are security risks which DCOM communication

I need some feed, and questions for our Networkadmins and Databaseadmins for first discussion

Thanks for all input, links and so on