---
title: "The RBL Checker for DNS Blacklisting"
description: "When you receive an email from another email address, InMotion Hosting email servers run a RBL checker on the receiving email against any known DNS Blacklisting companies. The RBL checker is..."
url: https://www.inmotionhosting.com/support/edu/cpanel/the-rbl-checker-for-dns-blacklisting/
date: 2013-05-17
modified: 2021-08-16
author: "InMotion Hosting Contributor"
categories: ["Blacklist Check", "cPanel", "DNS and Nameserver Changes"]
type: post
lang: en
---

# The RBL Checker for DNS Blacklisting

When you receive an email from another email address, InMotion Hosting email servers run a ***RBL checker*** on the receiving email against any known ***DNS Blacklisting*** companies. The *RBL checker* is different than [Spam Assassin](/support/email/spamassassin-fighting-spam/) or [Box Trapper](https://www.inmotionhosting.com/support/email/prevent-spam/) which is only for filtering and removing emails that go through to your server.

## What is an RBL?

An RBL is an Real-Time Black List or also called, a DNS-based Blackhole List (DNSBL), or Blacklist. Companies like [Spamcop](/support/email/stop-spam-spamcop/) maintain a database of IP addresses that are reported by consumers as being spam originators. To see the list of *DNS Blacklisting* company’s, please see our [Blacklist Checker](/support/tools/blacklist-check/). When the server scans an email and finds the sender to be on a blacklist the [email bounces to the sender](/support/email/email-bounce-bounceback-error/).

## Why does InMotion use an *RBL checker*?

**Using *DNS Blacklisting* companies is an industry standard**. Not only does InMotion Hosting uses *DNS Blacklists*; but, most email servers in the World use them. The *DNS Blacklist* company will keep a list of *known IP addresses* that have been reported and verified and sending spam from the server. This forces companies to regulate their servers to [prevent hacks](/support/questions/en/communities/1/topics/3433-email-account-hacked) and malicious activity from happening on their server.

## Can the *RBL checker* check be disabled?

We will not disable the *DNS Blacklist* checking on our [Shared servers](https://www.inmotionhosting.com/shared-hosting). The *DNS Blacklist* is the most effective way to keep our shared server customers from receiving unwanted spam from unknown senders.

[VPS](https://www.inmotionhosting.com/vps-hosting) and [Dedicated servers](https://www.inmotionhosting.com/dedicated-servers) on the other hand can have the *DNS Blacklist* check disabled in their *[EXIM](/support/email/manage-the-exim-mail-queue-in-whm/)* software. This will require [root access](/support/server/ssh/root-access-faq/) to change and knowledge of the [ssh command line](/support/server/ssh/how-to-login-ssh/). Our [Support](/support/amp/how-to-get-great-technical-support/) can disable the *RBL checker* for you if you cannot.

**IMPORTANT!** We do not recommend disabling *DNS Blacklist* checking on any server as this will allow any [email IP of known spammers](/support/email/ip-addresses-in-email-headers/) to email your server.

## Can Domain or IP addresses be *Whitelisted*?

We will not whitelist any domain or IP address that is on a known blacklist on our shared servers. Unfortunately, if a sender is on any known *DNS Blacklist*, they will need to contact their email service provider to have the IP delisted or contact the *DNS Blacklisting* company them self to have the IP delisted.

On VPS and Dedicated server, you can whitelist IP’s and domains for your *EXIM* to allow particular IP’s through to your server. This is a [root access](/support/server/ssh/root-access-faq/) change and would need [ssh command line](/support/server/ssh/how-to-login-ssh/) experience. You may want to [contact support](/support/amp/how-to-get-great-technical-support/) to have the domain or IP whitelisted.