Subject: Re: Multiple smarthosts for SMTP (sending from different accounts)
To: Steven M. Bellovin <>
From: Brian de Alwis <>
List: netbsd-users
Date: 01/31/2002 14:02:49
That makes sense. If somebody did spam from within the administrative
domain, presumably the admins could deal with that person. Thanks.

On 2002.01.31 15:37:30 -0500, Steven M. Bellovin wrote:
> I oversimplified:  it uses domain names for destination addresses, but 
> IP address for origination.  Someone is an insider if they are (a) on 
> the right network(s), which is (presumably) under the control of the 
> administrator, or (b) receiving mail in that domain, which is 
> definitely under administrative control.  You can't use domain name for 
> source-checking, or the spammers will send all their mail as being from 
> or what have you.  Heck, they'd just send it as being 
> from root, and let the sending site fill in its domain name.
> 		--Steve Bellovin,
> 		Full text of "Firewalls" book now at

"Source code in files. How quaint." - Kent Beck
"Maybe this world is another planet's Hell." - Aldous Huxley