On Fri, Jan 09, 2004 at 08:27:44AM -0500, Matt wrote:
|
| On a mail server with over 40,000 users it's relitively easy for someone
| with a password cracker to hammer away at common names like 'joe'
| 'jeffp', etc and try to get some passwords. Once they have a
| username/password combo they can happily send e-mail out as that user
| through MY mail server, and I can't do anything about them. Doing IP
| filtering requires that they are on MY network to send mail through MY
| server, thus allowing me to terminate/prosecute/etc the person.
We have to assume that the time will come when spam engines on
compromised Windows machines will try to send spam using SMTP AUTH
through the ISP's mail server, as well as directly through port 25.
Some worms and viruses already do this. So your scenario is very real.
Then the good guys will just gain another point of control. Others have
pointed out that ISP MTAs can then rate limit outbound mail. This
capability is well on its well in most MTAs today.
You can still terminate the account whether or not they come from your
network.
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