how to fight fake email addresss?

[Jason]

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Hi,

    For example an email is sent from someone at somehost.com. To make sure it
is not from a fake domain, check up someone.com to see whether it has the
same ip as the ip this email is sending from. Although it is still possible
that someother at somehonst.com faking someone at somehost.com, but at least the
email is coming from somehost.com

Jason

----- Original Message -----
From: "Ugo Bellavance" <ugob at CAMO-ROUTE.COM>
To: <MAILSCANNER at JISCMAIL.AC.UK>
Sent: Friday, October 15, 2004 10:53 PM
Subject: Re: how to fight fake email addresss?


> Jason wrote:
>> Hi,
>>
>>    I'm curious to know whether MailScanner will do a DNS lookup to make
>> sure the sender's domain matches its ip.
>
> What do you mean exactly?  Check that the domain exists?  That's the
> MTA's job.  Check that the smtp server used is the good one?  That is
> SPF and there are SPF rules in SpamAssassin.
>
>>
>> Jason
>
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