Re: Spam sent from outside to our internal users, from our internal users addresses!!! E2k

From: Lanwench [MVP - Exchange] (lanwench_at_heybuddy.donotsendme.unsolicitedmail.atyahoo.com)
Date: 02/18/04 

Date: Wed, 18 Feb 2004 11:49:27 -0500

I don't usually allow anyone or anything to relay through the Exchange
server - if there's a specific machine on the network that needs it, I'll
add its IP address. For Exchange to send outbound mail, you don't need to
allow anything to relay through it.

I don't enable authenticated relay, either - see
http://www.vamsoft.com/orf/authattack.asp. Have any external POP users use
their own ISP's SMTP server to send outbound mail.

Again, the issue you're having has nothing to do with relay. Someone is
spoofing the sender, and sending inbound mail to your domain. Your server is
by default set up to accept inbound mail from any server - if you start
modifying that, you likely won't get any inbound mail at all.

Is there something happening that makes you think you're being relayed
through?

Jason L. wrote:
> How do I configure the authentication for SMTP? I've been told the
> best practice is to just allow the internal subnets to be the only
> ones allowed to relay. This doesn't address relaying INto my domain,
> only relaying OUTside, it seems
>
> Thanks in advance,
>
> -Jason
>
> "The Mind is a Terrible Thing To Taste"

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