What is it?
Blacklisting is a word that’s commonly thrown around in the e-mail spam filtering world, so I figured I’d shed some light on what exactly it is. Those on the blacklist have their email blocked. “Blacklists” also go by a couple other names, such as: DNSBL (DNS-basedBlackhole List) and Block List. These lists are comprised of the IP addresses of computers and networks that have been linked to spamming, and are constantly updated. Most blacklists block at the server (IP address) level and not the individual e-mail address. Thus, if one email address in your organization gets flagged, then you run the risk of having all of your email addressed flagged. Typically, spam-filtering software, such as ourProSpam e-mail filter, can be configured to access these lists and automatically reject or flag e-mails from domains on these lists.
Who they target
Spammers tend to not have a specific target market; however, in recent time fraudulent spam has become increasingly popular. There’s a lot more money inacquiring and selling someone’s financial information than selling them cheap knockoffs of Viagra. In the field of computer security, phishing is the criminally fraudulent process of attempting to acquire sensitive information. Of the most phished organizations, JP Morgan Chase comprises 23% and Western Union comprises 17%. Also, spammers have been increasingly focusing on social networks like Facebook and Twitter. In fact, “Facebook is the second most phished organization online and, if current trends continue, is on track to take the top spot in 2010.” Since social networks work on the personal level, a hacked account gives spammers direct access to potential “clientele.”
How do domains get blacklisted?
For an IP address to get on a blacklist, there must be a steady flow of content deemed as spam coming from it. This spam usually comes from computers that are infected with mass mailing viruses and rootkits.
How can I check to see if I’m blacklisted?
MxToolbox has a tool at http://www.mxtoolbox.com/ that allows you to look up the IP address of your web server and then compare it against 147 DNS basedblacklists.
I think I’m blacklisted, what can I do?
To get “whitelisted,” you must attempt to contact each blacklist administrator and plead your case to them. The issue is not finding out which blacklists you’re on, but finding the proper contact information to get in touch with those who hold the blacklist fate of your IP address. This is obviously a time consuming ordeal that should be avoided at all costs.
Outbound Spam Filtering – Protecting you and your colleagues
What you send out through e-mail is just as important as what you receive. If a computer in your organization is infected with a virus, there’s a large chance that this virus will use your machine to send out
spam. This can happen before you even recognize that your system is infected. Spam sent from a corporate e-mail not only damages a company’s credibility, but can also get their domain “blacklisted.”
How do I prevent getting blacklisted?
The best way to not getting blacklisted is prevention. Utilizing antivirus software on your computer(s) is a no-brainer in properly protecting yourself from a virus. Also, it’s important to have an “outbound” spam filter. An efficient method is to have server-level email spam filters that use outbound filtering. This means that in the event your computer does get compromised, the outgoing filter will block an email that it flags as spam. In the event that an outgoing e-mail is flagged as spam, it will be blocked (but not deleted) and
you’ll receive a notification of the blockage.
For specific software recommendations that address both incoming and outgoing spam, please email heid@provim.net with subject heading Preventing Blacklisting.
Heid
ProVim
(317) 407-00302
heid@provim.net
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