how to stop spammers from spoofing our domain?

Spammers are starting to spoof our domain a lot, so xyz@ourdomain.com is
coming through but itâ??s spam. Is there a way to allow only emails in the
Global address book to come through and filter anything else that comes from
a bogus ourdomain.com address?

we have Exchange 2003 with SP2


TIA

Martin
Wed May 07 12:07:07 CDT 2008

The very design of SMTP allows anyone to spoof anyone.
But in your situation, you may want to look at filtering.
http://www.msexchange.org/tutorials/Sender-Recipient-Filtering.html
That will explain both sender and recipient filtering.

"XYZ" <XYZ@discussions.microsoft.com> wrote in message
news:3C4293BE-4492-4036-A439-2FD2F69C28A4@microsoft.com...
> Spammers are starting to spoof our domain a lot, so xyz@ourdomain.com is
> coming through but itâ??s spam. Is there a way to allow only emails in the
> Global address book to come through and filter anything else that comes
> from
> a bogus ourdomain.com address?
>
> we have Exchange 2003 with SP2
>
>
> TIA

XYZ
Wed May 07 12:21:02 CDT 2008

thank you
that is a great article!

btw, do you reccomend implementing SPF,,as additional protection from
rrogue/spam mail servers?

"Martin Blackstone" wrote:

> The very design of SMTP allows anyone to spoof anyone.
> But in your situation, you may want to look at filtering.
> http://www.msexchange.org/tutorials/Sender-Recipient-Filtering.html
> That will explain both sender and recipient filtering.
>
> "XYZ" <XYZ@discussions.microsoft.com> wrote in message
> news:3C4293BE-4492-4036-A439-2FD2F69C28A4@microsoft.com...
> > Spammers are starting to spoof our domain a lot, so xyz@ourdomain.com is
> > coming through but itâ??s spam. Is there a way to allow only emails in the
> > Global address book to come through and filter anything else that comes
> > from
> > a bogus ourdomain.com address?
> >
> > we have Exchange 2003 with SP2
> >
> >
> > TIA
>
>

Martin
Wed May 07 12:24:49 CDT 2008

I don't use SPF to score inbound mail.
Lots of people don't have SPF records configured and more have it configured
wrong.
I do have a published record myself (and hope its not wrong!)

"XYZ" <XYZ@discussions.microsoft.com> wrote in message
news:A250EC32-334A-4767-92BC-0C5D7FC46E4D@microsoft.com...
> thank you
> that is a great article!
>
> btw, do you reccomend implementing SPF,,as additional protection from
> rrogue/spam mail servers?
>
> "Martin Blackstone" wrote:
>
>> The very design of SMTP allows anyone to spoof anyone.
>> But in your situation, you may want to look at filtering.
>> http://www.msexchange.org/tutorials/Sender-Recipient-Filtering.html
>> That will explain both sender and recipient filtering.
>>
>> "XYZ" <XYZ@discussions.microsoft.com> wrote in message
>> news:3C4293BE-4492-4036-A439-2FD2F69C28A4@microsoft.com...
>> > Spammers are starting to spoof our domain a lot, so xyz@ourdomain.com
>> > is
>> > coming through but itâ??s spam. Is there a way to allow only emails in
>> > the
>> > Global address book to come through and filter anything else that comes
>> > from
>> > a bogus ourdomain.com address?
>> >
>> > we have Exchange 2003 with SP2
>> >
>> >
>> > TIA
>>
>>

Rich
Wed May 07 20:40:42 CDT 2008

XYZ <XYZ@discussions.microsoft.com> wrote:

>thank you
>that is a great article!
>
>btw, do you reccomend implementing SPF,,as additional protection from
>rrogue/spam mail servers?

That depends on who you allow to use your domain name, and from where
they send their email.

If you have employees that travel, or work at home, and they use thier
own ISP to send email using your domain then you'll have a user
education problem to deal with. If they use your email server as a
SMTP relay you won't have a problem with SPF but you'll have to deal
with restricting (or allowing) the use of your relay server.

From a company perspective, I think it's a good thing overall. There
are a few bumps and glitches, but there are more pros than cons.

--
Rich Matheisen
MCSE+I, Exchange MVP
MS Exchange FAQ at http://www.swinc.com/resource/exch_faq.htm
Don't send mail to this address mailto:h.pott@getronics.com
Or to these, either: mailto:h.pott@pinkroccade.com mailto:melvin.mcphucknuckle@getronics.com mailto:melvin.mcphucknuckle@pinkroccade.com

Rich
Wed May 07 20:48:00 CDT 2008

"Martin Blackstone" <martinb@myrealbox.com> wrote:

>I don't use SPF to score inbound mail.
>Lots of people don't have SPF records configured and more have it configured
>wrong.

Well, I would go quite that far. There are incorrect SPF records out
there, but I don't think there are enough of them to make SPF
unusable.

>I do have a published record myself (and hope its not wrong!)

Easy enough to check! http://www.openspf.org/Tools

--
Rich Matheisen
MCSE+I, Exchange MVP
MS Exchange FAQ at http://www.swinc.com/resource/exch_faq.htm
Don't send mail to this address mailto:h.pott@getronics.com
Or to these, either: mailto:h.pott@pinkroccade.com mailto:melvin.mcphucknuckle@getronics.com mailto:melvin.mcphucknuckle@pinkroccade.com