Over the last several weeks we have been analyzing mail patterns in our continuing effort to improve our spam filters. As some have recently noticed, the result of our daily investigations into the sources of spam is having a major impact on the amount of junk getting through to your inbox.
The vast majority of spam on the internet is sent via virus infected computer systems called spambots. Thousands of computers using DSL or cable, even dial-up, infected by a spammer's virus are then used to send out massive amounts of spam on a daily basis.
The major spambots on the internet are outside the United States, and some of these networks are notorious for the number of infected computers connected to them. The language barrier complicates matters both in bringing the problem to the attention of network administrators, and in educating the owners of these infected computers. The results are large chunks of the global Internet that are so heavily infested that the only reasonable defense against the sheer volume of traffic originating from these networks... is a total quarantine. The following networks, in whole or in part, have been blocked from sending mail to Avvanta mail servers (in no particular order): - Turk Telekom (ttnet.net.tr - Turkey)
- Telecomunicacoes De Sao Paulo (telesp.net.br - Brazil)
- Telecom Italia (telecomitalia.it - Italy)
- Telecentro (telecentro.com.ar - Argentina)
- CNC Group (cnc-noc.net - China)
- Telekomunikacja Polska (tpnet.pl - Poland)
- Vietnam Post and Telecommunications (vnpt.com.vn - Vietnam)
In addition, we've blocked the dynamic IP allocations of the following US service providers. Note that this will not stop people on these networks from emailing you legitimately using their regular mail servers. If however their own computer attempts to connect directly to our mail server from their home machine, the servers here will refuse the attempt.- Comcast (comcast.net)
- Road Runner (rr.com)
- Verizon (verizon.net)
- Bell South (bellsouth.net)
- SBC Global (sbcglobal.net)
The above blocks will not stop legitimate mail sent by users of the above ISPs. These blocks are specific to dyanamic IPs assigned to home DSL or Cable internet connections. Mail sent from those home computers directly to our mail servers is almost guaranteed to be spam and will be refused.The effectiveness of these measures were felt almost immediately. In February of this year our spam filters hit the one billion mark after nearly 4 years, averaging about 250 million messages per year. Since that milestone the filters have stopped an additional 394 million messages. To put that into perspective the filters have stopped more mail in the last four months than they did in the last year. We will continue to improve upon our efforts in the never ending battle against spam and junk. Help us out! Enable your Advanced Spam Protection rules. You can improve their performance for you personally with our Spam Filtering Tips and Tricks. And remember, use the Delete As Spam button of the CCC on the spam that does make it into your inbox. We use that data to not only fingerprint the spam for the RAZOR2 database, but to also fine tune our IP blocking efforts. If you have questions about our filtering or if you feel that a sender has been blocked in error, please let us know.
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