Timothy Alberts wrote:
Thank you for the response Paul.
I like the idea of blocking an IP range, as I'm already doing that for
several spammers. However, when I blocked on IP, they changed IP to
200.206.123.10. I could try and block multiple IP ranges, but it's just
a moving target I think. I block one and they move to another. I don't
want to have to play that game.
So if sendmail finds that it can't trust the name (DNS fails in some
manner), is there a way to configure sendmail to REJECT the mail as it
is coming in based on failed DNS, rather than block IP ranges?
Technically this is possible, but you'll very likely find that you lose
a lot of mail you actually want if you do that, since many sites still
have broken rDNS.
You might have better luck using a blacklist, such as SBL-XBL
(http://www.spamhaus.org/xbl/index.lasso). You can configure this in
sendmail.mc as follows:
define(`DNSBL_MAP',`dns -R A')dnl
FEATURE(`dnsbl',`sbl-xbl.spamhaus.org',`"550 Mail from your server
rejected - see http://www.spamhaus.org/query/bl?ip=";
$&{client_addr}',`t')dnl
(the FEATURE is one long line)
P.S. Please don't top-post on this mailing list.
Paul.
