Re: [Exim] dhcp-hosts in reject_hosts

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Autor: Giuliano Gavazzi
Datum:  
To: admin, exim-users
Betreff: Re: [Exim] dhcp-hosts in reject_hosts
At 10:55 +0100 2003/01/03, admin wrote:
>Hello all,
>
>Does anybody know whether it's possible to place dhcp-hosts in the
>reject_hostst file, of another way to solve this?
>The problem is that I recieve a rather large amount of virusses from a
>sender who hasn't got a static IP#, but recieves one through a
>dhcp-server from his ISP. Although he hasn't got a static IP#, he has
>got a hostname like user###.cable.isp.com. Is it possible to reject mail
>from this user-domain?


yes, use a deny condition in acl_smtp_rcpt (see spec.txt in the docs).
Let's stop being nice

deny message = No cable/dsl/modem users, use your ISP smtp server instead
            note the absence of "please" ^^^^
      condition =   ${if match\
                {$sender_host_name}{\N[0-9]{3,}.*(cable|dsl|ppp|slip)\N}{1}{0}}


you will not find any regular server with that pattern, the last
famous words... And the above is not tested and probably will break
your conf file.
If you really want to accept servers which are, to their misfortune,
on a cable/dsl connection, then let them be but only if the direct
lookup of their HELO argument matches their IP. If they think they
can be lazy, let them know..

>
>Ofcourse I would not want to ban all users of this ISP and the
>virus-sender does not send the virusses through his own e-mail address,


yes you do. Why would a user contact directly you smtp server? They
should use their ISP's. You are not banning a sender, you are barring
a group of hosts.
Just remember to check the conf before hupping exim. (Having said so,
it looks like exim checks changes like the inclusion of new files
without need for SIGHUP).

I had something else to say but I forgot...


>Thanks in advance for any answers.
>With kind regards,
>
>Thijs


There are plenty of other solutions, mine is better not used (I
don't), besides: most spam/viruses come from other sources.

Giuliano