At some point you may have received an error message that an email has been blocked from going to recipient with the following message:
554 5.7.1 Service unavailable; Client host [18.104.22.168] blocked using dnsbl-1.uceprotect.net
Who They Are
UCEProtect is a DNS blacklisting service that is made up of three distinct levels (1, 2 and 3). They have aggressive listing policies and can frequently blocks entire subnets or any associated IPs.
Issues Arising from UCE Protect
- do not publish why IPs are on their blacklist.
- do not reply or communicate.
- they have listed thousands of our IPs on their blacklist that have never relayed mail.
- charge a large fee to remove IPs from their blacklist.
- it can take up to 30 days for the blacklisting to drop off if you don't pay
- they like to block entire subnets of IPs and have been known to block most of Amazon, ISPs, telecoms providers and governments.
What to Do
MailRoute does not condone the pay-to-delist model blacklists. This is not a well respected practice in the email industry.
We can't control what other people use but we recommend that if you have someone in regular contact who is affected by this blacklist we ask that you reach out and ask them to not sure UCEProtect.
For More Information
Other Sources Regarding UCE