It’s no fun when you are told you (or a client) have ended up on a blacklist. It may be an IP address, a domain for a website or e-mail addresses, or something more general. Landing on a blacklist might mean clients running filtering software won’t be able to visit your website, for example, if your domain was being marked as hosting adult content. If you land on a blacklist for e-mail, it might mean that your users are not able to communicate with the outside world since those e-mails are considered spam.
The process to get off of a blacklist varies with each list and depends on the reason. The first step is to find out the reason you are finding yourself in this mess and who owns the list you are now on. Did a user fall for phishing and their account is non-stop spamming the world? Was your website compromised and is now serving up adult content? Clean up those problems. Next, contact the owner of the list that has flagged your IP/domain. Explain that the issue has been resolved and request to be taken off the blacklist. This process can take from a few days to several weeks. Blacklists can seem a bit like extortion because many list owners will allow you to pay an expediting fee to be removed from the list quicker. Paying that fee is up to you, the cost, and the urgency of your users.
Hopefully you are told by the filtering software which list you are on but that is not always the case. To find out which lists you are on, you might need to check across some of the big lists out there. Search across these lists from various companies and organizations to see if you can find the source.
- Spamhaus (IP or domain)
- CBL (IP)
- WhatIsMyIPAddress.com (IP)
- MX Toolbox (domain)
- FortiGuard Center (IP or domain)
- Blue Coat (domain)
- SURBL (domain)
- Cisco’s SenderBase (IP, domain, or network owner)
- Barracude Central (IP or domain)
- Trend Micro (IP)
- McAfee TrustedSource (domain)
- URLBlackList.com (domain)
- SquidGuard (d0main)
- OpenDNS (domain)
- rbls.org (IP or domain)
Many of these tools will search across dozens of blacklists which they don’t own, so make sure you contact the right people.
The problem could also stem from a bad configuration on the client. Most residential IPs are automatically added to blacklists. Users sending from a desktop e-mail client would need to configure their e-mail to send through their ISP or organization’s outgoing e-mail server.