The concept and workings of RBL (Realtime Blackhole List)

Written By Support Team (Administrator)

Updated at April 15th, 2022

Definition of RBL
 RBL stands for Realtime Blackhole List. RBL consists of servers where these servers have a list of ip addresses that carry out prohibited or abusive activities such as spamming. Mail server-mail server who wants to do spam prevention can use this RBL.

RBL function
On a mail server that uses RBL as a filter, when the mail server receives an email, from behind the scenes there will be a process of checking beforehand on the IP Address of the EMAIL sender, if the IP Address of the email sender is registered on the RBL list, the recipient's mail server will reject it. emails received, this really helps the server admin or email users in avoiding receiving emails that smell like spam which usually contains malware or code that harms the user's device, and the mechanism for checking IP addresses is the same as querying DNS.

The reason for using RBL is to prevent it because the process is simple, just looking for information about the IP.

Here's a list of the most popular RBL providers:


How RBL Providers Work

Providers registered as RBL have their own way of knowing an IP Address has a good reputation or not, one of the most common ways is to provide a server or dummy mail server whose function is to record log activity that occurs on that server.

Spammers will usually send massive emails, which if one of the destination emails reaches the mail server from RBL and if this activity is more than 1 time, the RBL system will classify the sender's IP address as having a bad reputation and add it to the blackhole list.

In addition to the above method, the RBL is usually also open to reporting information from internet users by sending an Abuse form or email information containing abuse log data, which if the data is valid, the process will continue to enter the IP Address into the blackhole list. .

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