Re: [exim] EXIM as bacup MX vs SPAM

I've had the same problems for some time,
I now use exim4 (I upgraded 2 months ago). I also liked to have mailboxes
resident on the secondary MX server. This way if the primary server is down
users can consult their mail on the secondary (via webmail checking local
mailboxes). And periodically (every 5-10 minutes) the primary servers of each
domain use fetchmail to get mail from the secondary.
On the secondary server I have to mantain a directory for each domain
mailboxes and a file for each user on that domain. This way if exim finds a
file name "account" in directory "domain.com" it knows account@???
exists if there's no such file named "account" a permanent error is given to
the sender in SMTP time. About 35%-45% of emails are rejected because "there
is no such user in that domain" and I also check sbl.spamhaus.org as RBL
before checking if user exists. My secondary server (now I use it for about
10 domains but they will grow to about 50) rejects 90-95% of emails trying to
enter the system. And it does this at SMTP time (spamassassin, clamav, check
existence of users, rbl)...

To do so (check users) on exim4 I have a router:

virtual_user:
debug_print = "R: virtual_user for $local_part@$domain"
require_files = /home/${domain}/mail/${local_part}
driver = accept
domains = /etc/exim4/virtual_domains
transport = virtual_delivery


And a transport:

virtual_delivery:
driver = appendfile
user = 1000
group = 20000
mode = 0660
mode_fail_narrower = false
envelope_to_add = true
file = /home/${domain}/mail/${local_part}
file_must_exist = true

And one more router for aliases:

virtual_aliases:
debug_print = "R: virtual_aliases for $local_part@$domain"
driver = redirect
domains = /etc/exim4/virtual_domains
allow_fail
allow_defer
data = ${lookup{$local_part}lsearch{/home/$domain/etc/aliases}}
modemask = 002
owngroups = domini
owners = domini
qualify_preserve_domain = true
# user = list
# group = mail
file_transport = address_file


For pop (fetchmails) i use teapop, this line in teapop.conf allows pop for
domain domain.com:

domain.com:*:htpasswd:/home/domain.com/mail:0:20000:20000:/home/domain.com/et
c/passwd:9999:

You can check the documentation of teapop in debian, there's a howto for
configuring this for exim3 but you won't check por virus and spam at smtp
time...

A Divendres 20 Maig 2005 09:56, David Strobl va escriure:
> Hello everyone,
>
> can anyone help me with the next problem?
> I use Exim 3 (Debian Woody) as backup MX mail server for two domains. Is it
> possible to give to exim the list of the valid e-mail addresses? Some
> spammers trying to use random user name with name our domain and I looking
> for way to eliminate it. I Still use the DNSBL(spamhaus.org) and it seems
> it is not enought.
>
> Thank's for advice and any kick.
>
> David

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