Re: [Exim] Rejecting forged local addresses

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Author: Dave C.
Date:  
To: Jeremy Koch
CC: exim-users
Subject: Re: [Exim] Rejecting forged local addresses
On 17 Jul 2002, Jeremy Koch wrote:

>
>     Hello,

>
> First, thanks to everyone who helped make Exim possbile. It is a
> wonderful MTA.
>
> It seems the latest ugly trend in spamming is forging the sender address
> so it appears as though the mail is originating in from the local
> domain. Example: Mail is addressed to jjk@??? from
> jjk@???.
>
> What I need to do is check the senders domain against my list of local
> domains. If a match is found check the senders IP against
> host_accept_relay. If the senders domain is considered local and
> senders IP matches host_accept_relay the message is accepted. Clear as
> mud? To put it anther way - If the senders IP is not found in
> host_accept_relay and the senders domain is local the message gets
> rejected.
>
> Any advice/thoughts would be appreciated


You'd also need to allow for SMTP AUTH from arbitrary IP's, if you
support it (or if you plan to)..

You'd also need to allow for mail posted to mailing lists by your users,
which might leave the sender as your user when sending it to the
subscribers (which would presumably often include the person making the
post)

>
> Thanks,
>
> --
>
> -Jeremy
>
> [ 1cd63c5ddff1bf8ce844237f580e9cf3 ]
>
>
> --
>
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