Spam Attacks

[Paul Kelly :: Blacknight]

Hi Guys,

Has anyone noticed a huge increase in smtp slamming recently?

We have a busy mail cluster that has about 80k users. In the last 10 days or so we've seen a huge increase in IPs slamming the mail servers. The really odd thing is that it happens a few times a day and it's really intensive. Mostly the traffic hops off of RBL lookups. As an experiment today I moved 8 domains MX records to a stand alone Postfix box with just zen.spamhaus.org configured on it.

The results are _insane_, a snippet from just today.

Per-Hour Traffic Summary
------------------------
    time          received  delivered   deferred    bounced     rejected
    --------------------------------------------------------------------

    1000-1100          12          0          0         19       1776 
    1100-1200          26          1          0        112       2851 
    1200-1300          25          5          0         54       3256 
    1300-1400          66          1          0        200      13509 
    1400-1500         241          0          0        501      61974 
    1500-1600         229          3          0        520      55902 
    1600-1700          38          1          0         74       3750 
    1700-1800         197          2          0        441      47213 
    1800-1900         302          3          0        638      77602 
    1900-2000         134          6          0        248      38728 
    2000-2100          23          1          0         63       4482 
    2100-2200         169          4          0        216       2786 

Is anyone else seeing this?

Cheers,

Paul

Paul Kelly
Technical Director
Microsoft Certified Partner
Blacknight Internet Solutions ltd
Hosting, Colocation, Dedicated servers
IP Transit Services
Tel: +353(0)599183072
Lo-call: 1850 929 929
DDI: +353 (0) 59 9183091
 
e-mail: paul at blacknight.com
web: http://www.blacknight.com
 
Blacknight Internet Solutions Ltd,
Unit 12A,Barrowside Business Park,
Sleaty Road,
Graiguecullen,
Carlow,
Ireland
 
Company No.: 370845