Since 28-Oct-2016, we’ve been receiving reports of inconsistent results from the following blacklists:
– dnsbl-1.uceprotect.net
– dnsbl-2.uceprotect.net
– dnsbl-3.uceprotect.net
– ips.backscatterer.org
Upon further investigation of these reports, we found out that the above RBLs had stopped responding to DNS queries and presently return null results when looking up their A DNS records.
This can be confirmed by doing a simple look-up via G Suite Toolbox here:
https://toolbox.googleapps.com/apps/dig/#A/dnsbl-1.uceprotect.net
https://toolbox.googleapps.com/apps/dig/#A/dnsbl-2.uceprotect.net
https://toolbox.googleapps.com/apps/dig/#A/dnsbl-3.uceprotect.net
https://toolbox.googleapps.com/apps/dig/#A/ips.backscatterer.org
While we have been monitoring UCEPROTECT & BACKSCATERRER for years on behalf of our users without failure whatsoever, we believe that DNSBLs should at all times maintain consistent behavior and do not change the way they respond to queries for whatever reason.
That being said, we have decided to temporarily exclude the aforementioned blacklists from our monitoring process because at this point we do not deem them to be reliable and trustworthy.
We are going to keep a close eye on the availability of the above DNSBLs to see if they would return back to normal. In case UCEPROTECT & BACKSCATERRER do not resume stable operation, we will permanently exclude them from our monitoring list, and we will begin to discourage all ISPs from relying on their output.
Meanwhile, if you see any real cases where e-mail messages are being blocked due to UCEPROTECT & BACKSCATERRER blacklisting, please do feel free to contact us so we can investigate further and provide advice on the best course of action.
