Google Groups analogue for intranet?

Question

Google

Please tell me, an analogue of Google Groups, which can be raised on the intranet (within the company).
I would like to organize discussions, have access from the mail (via mailing lists) and through the browser to the archive of discussions. A good analogue of what you need is Google Groups.
The proven MailMan offers something similar, but it looks rather scary (both in terms of configuration and in terms of viewing the web interface).

Answer 1

There is also Sympa

Answer 2

newsgroups server?