Sendmail / alias issue

[Giorgos Keramidas]

On 2006-03-08 11:15, Nathan Vidican <nvidican at wmptl.com> wrote:
> I know there might be a better sendmail/related mailing list to send this
> to, but figured I'd drop it here and give it a shot - sorry for the cross
> post, but I subscribe to -questions so figured it'd be okay and beneficial
> to other users too. Anyhow, on with the problem:
>
> I have an entry like this in /etc/mail/aliases:
>
> someolduserwhoquit:	550:"The user you have attempted to send mail to no \
> 			longer exists on this system, please see\
> 			http://www... for details or a new contact"
>
> (not exact; in alias file it's all on one line with no \ )
>
> alias works exactly as expected; when someone sends a message to
> someolduserwhoquit at wmptl.com, it bounces their message back with the error
> string I quoted. The problem then, becomes SPAM (lol - when is SPAM NOT a
> problem eh?).
>
> example:
>  - (faked) from: somefakeid at yahoo.com
>  - sends a message to someolduserwhoquit at wmptl.com
>  - tries to bounce message back, in-turn getting message bounced back to
>    our postmaster saying 'no valid user here for somefakeid at yahoo.com'
>
> So, to the question part... how can I setup an alias to either ignore the
> bounce-back it gets, (ie to blindly send the bounce itself), or is it
> possible to specify a different from address on our server's end so when/if
> the other receiving server doesn't have a valid from address it just drops
> the reply on our end, like so:

I prefer using a different error code that is not a "permanent error".

A "transient error" forces the SMTP relay of the spammers to keep the
message for some period in their queue and try again later.  There's no
need for you to keep the message in your own mail queue :)