On 10/20/2014 02:41 PM, francis picabia wrote:
On Mon, Oct 20, 2014 at 9:18 AM, Robert Moskowitz <[email protected]
<mailto:[email protected]>> wrote:
SInce this is about mail and spam, I thought this might be a good
place to ask about nolisting:
http://en.wikipedia.org/wiki/Nolisting
I get ~ 7000 messages/day on my server, with ~70% getting tagged
as spam.
This is really private mailserver for my side consulting business
and for all the standards and support lists I am on.
I am in the process of building a new server that I hope to launch
tonight: Redsleeve6 (on
armv7/Cubietruck)/postfix/dovecot/spamassassin/clamav/amavis-new.
I a friend recommended I use nolisting to reduce the amount of
spam messages to scan for spam. I tried the single fake MX record
as discussed in the wiki. Port 25 is blocked on the first MX
entry. No changes in spam received.
So I was told that this simple single MX record may not work. To
have TWO fake low value MX records and one high value like:
MX 10 bad.foo.com <http://bad.foo.com>
MX 20 bad2.foo.com <http://bad2.foo.com>
MX 30 me.foo.com <http://me.foo.com>
MX 40 bad3.foo.com <http://bad3.foo.com>
And this did not make any difference in % of spam. I seem to be
receiving the same amount. So either the spammers that know about
me use realy MTAs or have updated their SMTP to process MX records
right.
So is there any experience here with nolisting?
thanks
We ran nolisting set up for a number of years. It worked about as well
as reverse DNS checks for eliminating spam, without the CPU overhead
of reverse DNS check. The problem is, this does nothing about spammers
who decide to run a real mailqueue, or abuse someone else's mail server,
which is increasingly the case.
First I finally figured out that it is helping some. Those numbers I
gave were from logwatch amavis-new messages. When I look at actual
postfix message numbers, I get a different picture. Before nolisting,
postfix was dealing with 21k messages. After nolisting it dropped to
15k. That is a pretty good improvement, but a lot of messages received
for amavis-new to pass only 2k messages to user accounts! So much noise
out there. Oh, for those peaceful days when I set up my first server in
'94... ;)
As one person pointed out, over the years I have learned so much and
remembered so little. All too true.
Eventually we implemented a real grey lister, sqlgrey with Postfix.
The results were worthwhile. The email delivered by our secondary MX
fell from
about 5000 per day down to 200 or so. It was so alarming I was afraid we
would hear from users on missing mail, but it really was all spam.
I will look into these.
Our solution is Postfix with postscreen (eliminates zombies that don't
behave like a mail server), sqlgrey (eliminates systems that don't queue)
amavis with SA and clamav, RBLs like spamhaus, plus SANE security
add ons for clamav.
When I eliminated the nolisting config with all the above in place,
spam and email delivery stats did not increase.
While running with nolisting I think we encountered two sites
running home made mail software which didn't fail over to
the next MX and called us. Once we explained
why their software failed, they fixed it on their end.
thanks
