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To avoid such problems, there are online databases with lists of spam generators and malware programming. Most email servers use IP blocklists. It can be also useful for firewalls to evaluate the quality of income correspondence. Such lists will help to avoid suspicious traffic.
There are different lists and each of them uses its own strategy for data collecting. Some servers accumulate user statistics on the basis of clicks “This is spam”. The collected information is provided to the companies that manage block lists. Other operators use “honeypots” – special systems that work for spam attraction. They add any IP that sends emails to the list.
Many spam letters are sent from home PCs or infected devices that are recognized as a “botnet”. Operators may scan the network to find exploited devices. Home users and owners of cell phones don’t use email services. Thus, any sign that the IP is used for such activities may be a reason to move it to the block list.
The key issue about blocklists is the block of traffic. Several blocklists do it on purpose in order to make influential holders of IPv4 protect their clients from annoying content.
It happened that the device was put into the spam list but later was removed and the annoying content stopped. A huge number of blacklists have a time-limited policy. If during a certain period of time, there were no reports about spam, the address is removed from the base. In the case of repetitive reports, more time is required until the IP gets outdated.
Among IPv4 for sale, there can often come the ones in the block list. It’s better to check this aspect before purchasing. You should keep in mind that IPs can appear in the list or be removed for a certain reason. Even if you monitored the databases a few weeks ago, the present situation can be different.
Such resources have a webpage with an option to check the IP’s presence in the list. But with IPv4 65,536 it won’t work. Several sites provide software that can be downloaded to the local PC.
SORBS and Spamhaus are the biggest operators in this sphere. To get access to them, you’ll have to pass a test. They are operating DNSBLs (block list of Domain name service).
Users can send queries via DNS to get the code with the list where the checked IP is present.
To check the block, the script is required. It will query every IP of the block. For this, you may turn to a friendly service Interlir.
Each blocklist has a certain algorithm to delete the addresses. But in most cases, they’ll demand proof that the initial reason for listing is also removed. Some SORBS allow users to retest.
If the test is passed, SORBS will put the address to clean up. If there is no access to the computer with the necessary IP or the browser is absent, you may try to create a ticket, and send it to a support team.
Spamhaus also has an interface with information about the list and IP removal.
If you don’t want to do it yourself, use the broker services.