[Exim] Help

I would like to know what the command is to view exactly what is happening
at a specific time on the mail server. We have got various external users
emailing users within our network and it is utilizing our bandwidth. I can
see who the external user is, but I don't know who they are mailing to
within our network.
How do I find out who the recipient is, the file size, and the type of file
extension?
Your help will be greatly appreciated.

Thanks
Gareth