IP Blacklist Check
Check if an IP address is on common DNS-based blacklists (DNSBLs) in real-time.
Check an IP Address Reputation
Enter an IPv4 address to check its reputation across major DNS-based anti-spam databases (DNSBLs). Find out if your IP is on a spam list, which could hurt your email deliverability and get your messages blocked.
About IP Blacklists (DNSBLs)
What it means to be on a DNS-based anti-spam database.
A DNS-based Blacklist (DNSBL), also known as a Real-time Blackhole List (RBL), is a list of IP addresses that are known for sending spam or participating in other unwanted online activity. Internet Service Providers (ISPs), email providers, and web servers use these lists to filter out malicious and unsolicited traffic before it reaches you.
If your IP address appears on one of these blacklists, it means it has been flagged for suspicious behavior. This can severely impact your ability to send emails, as many mail servers will block or filter messages from a listed IP. This tool helps you quickly check your IP address against the most common anti-spam databases.
An IP address can get blacklisted for various reasons. It could be due to sending spam (knowingly or not, such as from a malware-infected computer), having an insecure server configuration, or simply because a previous user of your dynamically assigned IP address engaged in unwanted activity.