Something that often affects email users, is the reputation of the IP address that they are sending from. IP reputation is also utilized in a broader spectrum than just email, but that is primary service that is most affected by a negative IP reputation.
IP reputation is a term used to identify how likely a connecting computer intends malicious activity whether that is through spam emails, overwhelming amounts of connections, etc…
The goal here is to maintain a good or positive reputation with RBLs.
When an IP gains a negative reputation, more specifically gains a negative reputation across multiple RBLs, the IP has an increased likelihood of being rejected by servers. The servers that are adhering to these RBLs do so to protect their users from malicious IPs.
So if you are encountering an issue where your connection attempts or messages are being rejected and the cited reason is due to an IP reputation. The first thing to due to is to use a lookup tool to determine how your IP address’s reputation is being rated across multiple RBLs.
We recommend the use of the following Lookup tools. They are free and easy to use:
These tools will take the IP address that you enter and run it against its list of available RBLs to see what lists, if any, are reporting that your IP address has a negative reputation.
RBLs (Blacklists) are organizations that assimilate reports of negative behavior from IP address and then report that behavior to other systems to warn them that certain IP addresses may not intend legitimate interactions. These reports are what constitute the blacklist. These services are very useful in cutting down on successful malicious activity (successful, here meaning that an innocent user is affected by the mal-intent of a spammer or the like.)
Most prominent RBLs will allow you to delist your IP address from their blacklists; however, some will require a certain amount of time pass before they remove the IP address from the list. In those situations, if the offending IP is then continuously being reported by other servers of continuing the malicious behavior then the RBL will likely not delist the IP address. It is always best to ensure that your server is not hosting malicious scripts or a user that is sending out spam, whether that is with or without their knowledge.
Some of the more common RBLs are listed below: