Re: [exim] $h_from or $sender_addres

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Lähettäjä: Heiko Schlittermann
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Vastaanottaja: exim-users
Aihe: Re: [exim] $h_from or $sender_addres
Hi,

soumya tr <soumya.324@???> (Mo 17 Feb 2014 18:32:08 CET):
> Hi,
>
> I am in the process of adding some condtions to prevent from address
> spoofing. But now I am confused on weather to use $h_from or
> $sender_address .
>
> Which one should I use? Please help


The $sender_address is the envelope sender. $h_from gets its value from
the "From:" header.

Both may be forged.

The "From:" is even more forged mostly. (As many MTA take care about
checking the envelope sender in some way, but don't care about the
message headers.)

The $sender_address is guaranteed to contain a valid address (or is
empty, if the envelope sender was empty (bounce), since Exim extracts
this from the SMTP MAIL FROM command.

The $h_from contains that what the sender put into the "From:" header,
this can be literally anything. Except you do not use "verify = header",
Exim does not take care about the (syntactical) correctness of this
header.

To make it more complicated, the "From:" header may contain multiple
addresses, thus checking is more difficult, but possible.

And, if you receive your own message via a mailing list (like this
exim-users), it contains your own address in the "From:" header. But the
envelope sender (sender_address) is set to something like
"<exim-users-bounces+…@exim.org>". It's this should be far away from
spoofing.

Now it's up to you :)

    Best regards from Dresden/Germany
    Viele Grüße aus Dresden
    Heiko Schlittermann
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