Re: [gentoo-server] SMTP Woes

["Kerin Millar" <kerframil@gmail.com>]

On 30/11/2007, Arturo 'Buanzo' Busleiman <buanzo@buanzo.com.ar> wrote:
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> Randy Barlow wrote:
> > I am getting a huge number of connections to my mail server (postfix)
> > compared to usual.  I've seen as many as 50 connections open at one
> > time.  The logs show that the connections are from several computers of
> > varying IPs, and they are all trying to send mail to random mailboxes on
> > my domain.  It's very annoying, and I have noticed that inbound mail
> > seems to be lagging by several hours.  Is there something similar to
> > denyhosts for spammers?  Any other suggestions?
>
> Check those IPs against: www.robtex.com/rbl
> Choose your favorite blacklists (test them, some of them provide too many false positives) and
> implement with them DNSBL/RBL in your postfix. Also, SPF and greylisting make a good job.

Regarding SPF, I'd just like to add that the SPF policy daemons (which
can be integrated into postfix very easily) are available at
http://www.openspf.org/Software. There are implementations in perl and
python and, as luck would have it, the python version is available in
portage as mail-filter/pypolicyd-spf. If you choose to endorse SPF
then don't forget to define records for one's own domains! A helpful
document describing SPF syntax can be found here:
http://www.openspf.org/SPF_Record_Syntax.

Regards,

--Kerin
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