quick FW question

[Tim Aslat]

In the immortal words of D J Hawkey Jr <hawkeyd at visi.com>...
> Set up the mail server as the hub for your internal network, and have
> the workstations forward mail to it. If you're running sendmail on the
> workstations, put this in their .mc file:
>     define(`SMART_HOST', `smtp:mailhub.privatedomain')
> And rebuild their sendmail.cf (I use the same .mc file for all U**X
> boxen on my network, except for the mail hub). Basically, just point
> all internal boxen's mailers to the hub.

I'm using Exim, and I already have this part working (smart host)

> My mail hub, in turn, defines SMART_HOST to be my ISP's mail cluster,
> and I define MASQUERADE_AS to be my ISP's domain (I use the feature
> masquerade_envelope, too). You might not be able to do this, of
> course, it'll depend on your connectivity.

Not really required for this particular setup.

> You'll need an MX record set up for the mail hub in your DNS.

Got one :)

> Given the above approach, the only thing I have in my firewall for
> SMTP is a rule for stateful outbound on ports 25 and 995 (I use SSL-
> enabled POP3 to download incoming mail from my ISP's mail cluster).

Hmmm, that doesn't really solve my problem, but it's useful to have in
the archives anyhow.

What I want to do is grab any outgoing packets bound for a port 25 and
redirect them back to the local mailserver which has spam/virus
filtering.  This should eliminate problems of viruses/trojans which use
their own internal smtp servers to propogate themselves, coming from
this network.

The reason for this approach is the domain in question being RBL'd a
couple of days ago after one of the machines in this network had a
virus(actually a couple of thousand of various types).  

Cheers

Tim


-- 
Tim Aslat <tim at spyderweb.com.au>
Spyderweb Consulting
http://www.spyderweb.com.au
Phone: +61 0401088479