Blacklist Lookup

What is a blacklist check?

If you Google "blacklist check," you'll get a variety of results, from the MX blacklist lookup to RBL lookups that provide blacklisted domains. But an IP address blacklist check, or IP address blocklist check, is essentially an IP reputation check. The procedure shows if a URL or IP address entered aligns with a domain name server blacklist (DNSBL).

There are dozens of DNSBLs online, all using different criteria for listing and delisting addresses. However, the DNSBLs consider any IP addresses that exist on the lists a source of spam, resulting in the blocking of those addresses and their inability to send emails.

Spam filters utilize various DNSBLs to verify that incoming emails do not come from blacklisted sites, which would be a red flag. These domain name server blocklists are generally the first line of defense against IPs or domains sending spam. However, in some cases, the domain blacklist database adds addresses that don’t send spam. Users can utilize the free blacklist IP checker to find if the database wrongfully blocked their IP address.

How do I check if my IP is blacklisted?

Check blacklists for your IP address by entering the address into the tool above. If you don't know your IP address, the What's My IP address homepage shows you your IP address and its details. It also lets you conveniently copy and paste your IP into this tool to run a scan.

The IP blacklist checker tool will search IP blacklist sites and report a table of various blacklists. It lists the block status of each of your server IP addresses.

Domain name blacklists don’t notify users when their IP address goes on a blocklist. Users need to check name blacklists to find their status.

Therefore, blacklist checks are essential for users, mail servers, or businesses who believe that they have a blacklisted IP address. If your IP is blocked, you'll show up on the list. Using the tool above is the easiest way to check for blocked IPs.

How do I get my IP off a blacklist?

Even if someone added your IP to an IP address blacklist, you can still do an IP blocklist removal online. To fix a blacklisted IP address, first make sure that your network is free of malware, as databases sometimes blocklist IPs for infections users aren’t even aware of. If your network is clean, find the list that blacklisted your IP address and contact them directly for removal. After you make the request, check the blacklists again later to see if your IP remains on the list.

Each blocklist handles IP removal requests differently. You can't do a removal online, and unfortunately, databases can choose whether or not to honor requests; however, making a removal request still serves as the best method for clearing your IP address or mail server IP from the blocklist. If you’re an email system administrator with a blacklisted server, you need to work with the various DNSBLs that list you.

What causes IP blacklisting?

Blocklists add IP addresses for many reasons. The intention is to protect other websites and users from dangerous IP addresses. However, sometimes blocklists wrongfully list other IPs on the list. Therefore, a normal, safe IP is blocked. Then, a user who hasn't done anything wrong will see their address in an IP block lookup.

You may do a blacklist check online and find your own IP on a blacklist. A blacklist typically adds an IP for the following reasons:

• The IP appears to be the source of spam messaging
• The IP associates with a website containing inappropriate or dangerous content
• Your device has a malware infection, which then could spread to other devices on the network
• You accessed the dark web or other illegal trading sources with the IP

Blacklisting websites for spam protection

As mentioned above, domain name server blocklists are the primary defense against spam as they block IP addresses believed to be spam accounts. However, there are also spam uniform resource identifier blocklists (SURBLs) that serve as backup defenses. These blacklists note websites that appear in unsolicited emails. However, not all email spam filters have the capacity to use them.

Spam filters that can utilize the SURBLs scan the body text of emails, extract any website addresses present, and check them against blacklists. If the server finds an address, it flags the message as spam and handles it accordingly.

Since both methods filter spam differently, they are most effective when combined. Unfortunately, as spammers become more clever, there is no method capable of catching every spam message. 

Reporting IP blacklisting by analyzing email headers

It's useful to learn how to analyze email headers using an email header analyzer tool. These tools inspect and return a sender's IP address. If you receive spam messages or experience harassment online via email, use the analyzer tool to inspect the email header and report the address to the anti-spam blacklists.