Hundreds of domains managed by the UK government are on DNS-based blacklists. This creates problems with email communications.
Being on an automated "IP blacklist" usually indicates a problem with your email infrastructure: most likely either your server is sending spam or it has violated some point.
The "Domain Name System-based Blackhole List" (DNSBL) is a decentralized system with different servers around the world monitoring IPs that send spam emails to users.
These lists can then be searched through simple "DNS lookup queries" by mail servers to determine if an incoming email is likely to be spam.
This week, its user GitHub tg12 compiled a list of 8.481 GOV.UK domains and found that 450 of them were in one or more DNSBLs. BleepingComputer verified the IP addresses for a large number of domains listed and located them in a spam list.
However, the list provided by tg12 may need to be reviewed.
While most of the 450 domains listed are on one or more spam lists, some do not list.
The Reddit user wobblecapsule confirmed this since the bristol-city.gov.uk domain is not in any DNSBL.
Why are "IP blacklists" problematic?
Having a domain in DNSBL is problematic for an organization and even more so for government services, as this can prevent the proper delivery of emails.
If your organization uses shared hosting providers, that probably means a lot customers share the same IP address for their email and hosting needs.
Ultimately, this can affect an organization's reputation in addition to causing problems with email delivery.
As an organization, it is wise to check the DNSBLs regularly for the IPs of your mail server and preferably use a dedicated hosting to minimize the chances. add in a spam list.