A blacklist, as the name implies, is a list of people or businesses who have met with the disapproval of others. In the online world a blacklist refers to those all the people who have been marked as responsible for building spam in a very big way. Blacklists are also known as blocklists.

Blacklists are used to combat spam in a very distinctive way. When spam is reported to one of the relevant spam fighting organizations the IP address the spam originated from is added to a banned or blacklisted IP addresslist. An IP address is the unique location of you or your website on the internet - think of it as your "home address" online. To put it simply every www.domain.com Internet address has a matching IP address. Any electronic mail coming from your website domain also has a corresponding IP address. If your IP address is present on a blacklist then youre potentially wasting your time sending electronic mail to customers.

Why are you wasting your measure ? Modern spam blockers come with the most common blacklists installed and/or allow you to import updated blacklists into your spam blocker. This allows to you block a huge amount of spam but you might also, potentially, block legitimate e mail. Blacklists are not foolproof.

There are two types of IP address:

Dynamic - changes every instant you connect to the Internet. Most often used for dialup Internet access. Spammers love these because theyre very hard to track and 100% disposable.

Fixed/Static - All websites, most large companies and some individuals utilize fixed IP addresses. This may cause huge problems if theyre reported for spamming.

When an IP address (dynamic or fixed ) is reported for sending spam its added to a blacklist. There are three different types of blacklists:

Temporary

An IP address placed on a temporary blacklist will have e mail coming from that IP address blocked for several hours.

After a few hours the offending IP address is removed from the blacklist.

Permanent

When an IP address is added to a permanent blacklist any electronic mail server configured to block electronic mail from this list will never receive e-mail from that range of IP addresses again.

Comprehensive

This is the most damaging of blacklists. Not only does it block a single IP address it also blocks the IP addresses next to it. For example if the IP address 192.156.66.67 was added to a comprehensive blacklist then all IP addresses close to 192.156.66.67 will also be blocked. This can be a huge problem for those internet site owners using virtual hosting because if your host has ever appeared on a blacklist then youre also on the identical blacklist, by default, because of the shared hosting from the identical IP range. Its important for all internet site owners to check whether or not theyre on a blacklist. You will positive need your IP address (available from your webhost) and you might check your blacklist status at: www.mail-abuse.org/cgi-bin/lookup

Blacklists are a necessary evil due to the volume of spam being sent each day but are not an exact science. Take a few moments from your day and ensure that your web site or electronic mail address is not being blocked.

http://www.spam-site.com reviews and tests antispam software solutions for the business and finish user. Niall Roche is the content author and owner of spam-page .com