Blacklist monitors (DNSBL)

Enter an IPv4 address or a domain. For a domain, FastPing collects up to 3 IPv4 addresses from its A records and the first IPv4 address of up to 2 of its mail servers (MX records). Each address is looked up on 14 IP blocklists and the domain on 3 domain blocklists.

The monitor is down as soon as one list reports a listing, with a message such as Listed: 203.0.113.7 on bl.spamcop.net, and up otherwise (Not listed (14 lists checked) when an IP address is clean on every IP blocklist). Lists that refuse the query or do not answer are shown as unavailable and are not counted as listings. When no list answers at all, the result is No blocklist answered: that check does not count, the monitor keeps its status and no alert is sent. The check runs at most every 6 hours. IPv6 addresses are not supported.

Lists differ in how widely mail servers use them. A listing on a list used by many receivers, such as Spamhaus, tends to cause rejected mail quickly; a listing on a small list may have little visible effect, but it still tells you something sent spam from that address.

1. Find the cause first: a compromised mailbox or web form, an open relay, a script sending mail, or a bad mailing list. Requests to be removed are refused or the listing returns while the cause remains.
2. Check the list operator's website for the reason and the removal procedure for your address.
3. After removal, keep the monitor running. A second listing soon after the first points to a cause that was not fully fixed.

The free Blacklist check runs the same lookups once and shows each list's answer.