2 questions about sendmail

I use Redhat 9 and want to ask 2 questions:

1. I receive spam from logstoff.com. In /etc/mail/access I add

logstoff.com REJECT
62.216.181.67 REJECT

I make a new hashtable. But for all that I receive spam to the mail
account. Why?

2. I run a webshop (oscommerce). Sometimes (not always) I (and the
customer) did not receive the email with the order informations
generated by the PHP skript during the checkout.

Any idea?
Thanks
Florian

--
PM: f.schaeffer<at gmx.de>

On Thu, 04 Jun 2009 08:10:15 +0200, Florian Schaeffer wrote:

> I use Redhat 9 and want to ask 2 questions:
>
> 1. I receive spam from logstoff.com. In /etc/mail/access I add
>
> logstoff.com REJECT 62.216.181.67
> REJECT
>
> I make a new hashtable. But for all that I receive spam to the mail
> account. Why?
>
> 2. I run a webshop (oscommerce). Sometimes (not always) I (and the
> customer) did not receive the email with the order informations
> generated by the PHP skript during the checkout.
>
> Any idea?
> Thanks
> Florian

The SPAM side of things is a bit more nefarious -- you're only rejecting
the single address, and chances are the spam is coming from many, many
locations. Check out the "FEATURE(dnsbl", and get on the spamhaus.org
XBL list. That uses DNS to see if a host is listed as a spamming site,
and rejects connections from there. It's brought my spam to near 0.
You'll have to watch your logs, though, in case you're rejecting email
from valid customers. (The other way to go would be to use a bayesian
spam filter on your mail reader, which just might serve you better given
the environment -- lost email is lost sales, right?). Sendmail.org has
some nice walk-throughs to enable features -- getting XBL onto my system
wasn't more than an hour of so of work. (and it's been a great relief).

For your PHP script - I don't know PHP - but you'll probably want to
watch your mail logs closely if they're a vital part of your business
(see above). I find that using "logwatch" helps me keep an eye on
sendmail log entries (I have them mailed to me) -- it took me a while to
tune my configuration file "just so" -- but then that's served me for
quite a few years, and I get a daily/weekly summary of log entries that
I'm interested in (sendmail, ssh attempts, and other security related
things).

Watching your sendmail errors will key you in on (a) SPAM rejection that
is going on (to watch for false positives) and (b) any rejections from
remote systems. Keep in mind that users' own SPAM filters may be
filtering the message -- so always (a) ask them to check their spam box
and add you to the approved receivers, (b) keep an eye on those logs to
see if your site is being rejected. A decent "test" might be to have a
button on your site to "send me a test message" for people who think your
messages are getting picked up in SPAM buckets.

-- Tom