The Blacklist & SPAM Checker is a web-based reputation tool for testing whether a mail server IP address or domain appears on common DNS-based blacklists (DNSBL/RBL). It helps assess and monitor the sender reputation of email infrastructure to prevent messages from being blocked or delivered to spam folders.Purpose and Use Cases#
The tool is designed to quickly answer whether a given IP or domain is flagged as a spam source in one or more blacklist databases. Typical use cases include diagnosing sudden drops in deliverability, investigating user reports about emails landing in spam, and performing routine reputation checks on production mail servers.It is also useful as a preventive measure during onboarding of new IPs or domains, ensuring clean reputation before ramping up email sending volume.Users can enter either the sending IP address of their mail server or a domain name in a single input field. A configurable “Check Type” option allows automatic detection of whether the input is an IP or domain, or forcing the tool to treat the input explicitly as an IP or as a domain.This flexibility supports a wide range of setups, from dedicated outbound mail IPs to shared or domain-based configurations.Blacklist and Reputation Focus#
The Blacklist & SPAM Checker queries DNSBL databases that track IPs and domains associated with spam or malicious traffic. By summarizing these checks, it provides a clear indication of whether reputation problems might be causing delivery issues with specific providers or filters.Regular use of the tool helps maintain ongoing reputation monitoring, enabling teams to react quickly if an IP or domain becomes listed and remediation is required.Role Within Check My DNS#
This tool complements the other Check My DNS utilities by focusing specifically on sender reputation rather than raw DNS configuration. Together with the DNS and Email Host checkers, it offers a broader view of both technical correctness and how the outside world perceives a domain or mail server in terms of spam risk. Modified at 2026-02-07 14:19:20
