LashBack's unsubscribe blacklist ("UBL") is a unique, real-time blacklist of IP addresses which have sent email to addresses harvested from suppression files. There are approximately one million IPs on the UBL and it is updated on an hourly basis.
The listings are determined objectively and systematically. Only IPs that send email to specially-created, LashBack owned-and-monitored email addresses (unsubscribe probes) -- that are used only on suppression lists -- are blacklisted.
LashBack has been monitoring unsubscribe compliance for more than a decade and this effort has resulted in, what we believe to be, the world’s largest unsubscribe intelligence database.
Organizations use the UBL free-of-charge as a unique and important component in determining reputation and email delivery. LashBack maintains the UBL because of the importance of the reputation data and as part of its advocacy for best practices. The primary objective of the UBL is not revenue generation; in fact, the only fees charged are modest fees to repeat offenders. These fees discourage bad email and partially offset the expense of managing the blacklist.
If you have been blacklisted, then your IP sent email to a harvested email address. Either you know that it was done or you have a security issue. We let first-time offenders request the removal of their IP address free-of-charge, but if it happens more than once, there is a fee to request removal. If thirty days have passed without additional incidences, the IP is automatically removed from the list. We suggest that you make sure that any security issue is resolved before paying to delist. If you pay to delist and are immediately relisted, it is solely because we received new messages from the same IP address to our unsubscribe probes.
This service is a list of hostnames in the ubl.unsubscore.com zone. These hostnames may appear to be real IP Addresses. However, they are hosts in the ubl.unsubscore.com DNS zone.
In order to check whether an IP is listed in the UBL, you can perform a DNS query using the IP address of the sender. However, you must reverse the IP address in order to perform the query. For example, if you wish to check whether 192.168.1.100 is listed in the UBL, you would perform a DNS lookup on 126.96.36.199.ubl.unsubscore.com. If one of the DNS return codes listed below is returned, then the IP is listed in the UBL.
UBL Return Codes
Currently, the UBL supports the following return code: 127.0.0.2, which indicates that the IP address has sent email to a LashBack unsubscribe probe address.
Currently, the UBL allows anonymous zone transfers of ubl.unsubscore.com.
Mail Server Configuration
The UBL can be used for any mail server supporting connection-level blacklists. The blacklist server should be set to ubl.unsubscore.com.
DATA USE RESTRICTIONS
The UBL is provided free for both commercial and non-commercial use.
DISCLAIMER OF WARRANTIES AND LIABILITY
All data is provided for your personal information only, and not intended for legal purposes. LashBack, LLC (LashBack) is not liable for any errors in the data or for any actions taken in reliance thereon.
LASHBACK MAKES NO WARRANTY, EXPRESSED OR IMPLIED, AS TO THE RESULTS TO BE OBTAINED BY ANY USER OR OTHERS FROM THE USE OF THE INFORMATION PROVIDED HEREUNDER. LASHBACK MAKES NO EXPRESS OR IMPLIED WARRANTIES OF FITNESS OF THE INFORMATION FOR A PARTICULAR PURPOSE OR USE.
The information contained in LashBack databases has been developed by LashBack and is considered by LashBack to be reliable. However, the accuracy and completeness thereof are not guaranteed and LashBack and its data suppliers shall have no liability for errors or omissions regardless of the cause or source of such error or omission.
LASHBACK DOES NOT HAVE ANY LIABILITY TO A USER OR TO OTHERS FOR ANY LOST PROFITS OR INDIRECT, SPECIAL, CONSEQUENTIAL, PUNITIVE OR EXEMPLARY DAMAGES, EVEN IF ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES.
LashBack may change or discontinue the databases, or their availability to you, at any time without notice.
GET THE LIST
Get the list: UBL via XML | UBL via TXT
All downloadable files are available via RSYNC at: