On Thu, 17 May 2001, Yann Golanski wrote:
> On Thu, May 17, 2001 at 04:09:33PM +0100, Andy Coates quothed:
> > I've been given a task of setting up our mail server so that no one outside
> > our netblocks can send mail to someone in our company from a company email
> > address, e.g.
> > [...]
> > Having no idea even if this is possible or not, could anyone point me in the
> > right direction for the features and options I should be looking at?
>
> Look at the open relay section in the manual, it's all described there.
But consider this case:
1. Somebody inside your company sends mail to somebody outside your
company.
2. The message is allowed, and goes out.
3. The person outside your company forwards the message back to somebody
inside your company.
4. You now received a message from somebody inside your company, but
coming from a host outside your company, so you block it.
5. Grief all round.
Maybe this is unlikely to happen to you. In our case (large University,
over 20,000 users, several different mail servers and domains) it
certainly does happen.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
