Ultimate Hosts Blacklist for Network-Level Site Blocking

What UHB Blocks and Which Devices It Targets

Ultimate Hosts Blacklist, or UHB, addresses the problem of applying one large malicious-domain and IP blocklist across a network. Its stated audience includes people protecting computers, smartphones, Wi-Fi devices, children, and family networks. The repository publishes separate files for Unix and Linux hosts, Windows hosts in CRLF/DOS format, Pi-Hole-oriented data, and deny-file formats. This packaging matters because a single copy-and-paste workflow is not appropriate for every system.

The project describes itself as a unified collection gathered from multiple sources. Its current README lists 922,827 bad domains in `hosts`, 148,849 bad IP addresses in `hosts.deny`, and 1,071,676 domains and IP addresses in `superhosts.deny`. Those figures describe list contents, not a measured prevention rate. The documentation does not provide independent test results showing how often each listed destination corresponds to malicious behavior, whether every entry is still current, or whether a blocked domain may also support legitimate traffic.

UHB is therefore a blocking policy distribution rather than a security scanner. It supplies names and addresses for clients, operating systems, or network DNS configuration to reject. The repository's topic labels include malware, ransomware, adult content, drugs, violence, adware, clickjacking, and family protection. Its breadth makes accidental overlap with legitimate services a relevant adoption concern, especially on networks that depend on uncommon domains.

How UHB Moves From Blocklist to Client Resolution

The project offers two enforcement paths. With the hosts-file route, a client reads local name-to-address mappings before a request reaches the network's configured DNS service. A destination mapped to a blocking destination can therefore fail without changing the router. The repository separates Windows content into `hosts.windows`, while `hosts` is identified as Unix/Linux content. It also supplies `domains.list` for Pi-Hole and `domains-dotted-format/` as an additional representation.

The DNS route moves the blocklist to resolvers. The README identifies `safedns.allover.co.za` at `88.198.70.38` and `safedns2.allover.co.za` at `88.198.70.39` for IPv4, with matching IPv6 addresses. It lists ports `53` and `5353`. Both servers are described as operating around the clock without logging. The documentation also states that planned maintenance can cause downtime of less than 120 seconds and says the two servers will not be taken down together.

That DNS architecture reduces the need to update a local hosts file every night, which is the README's stated reason for choosing the service. It also creates an operational dependency on an external provider. The README publishes maintenance information through a linked Maintenance Thread, but it does not document DNS response filtering policy, caching details, domain exception handling, or measurement procedures. Those omissions matter when the DNS service is being considered for a family or organizational network.

Choosing a UHB File and a First Network-Level Use

The README does not provide a command-line installation tutorial or a documented one-command installer. Repository layout includes `Installer-Linux/` and `Installer-Windows/`, but the README does not explain how to run either installer, what privileges they request, or whether they alter backups and system files. A cautious first use therefore starts by obtaining the documented raw file and selecting the format that matches the target system.

For Unix or Linux, the documented file is `hosts`; for Windows, it is `hosts.windows`. The README also links official mirrors for both files. A reader looking for a Pi-Hole deployment should examine `domains.list` instead of assuming that a complete hosts file is the required input.

The DNS documentation supplies server names, addresses, and ports but does not include commands for changing DNS settings. Configure those values through the specific operating system or network management interface in use, then verify resolution for a listed destination and for a required internal service. The expected result of a block should be a resolution failure or destination substitution, although the documentation does not define the exact response returned by every client.

This first-use procedure is deliberately limited to documented values. It does not assume a package manager, cloning command, service name, backup path, or installer flag that the repository does not state.

Daily UHB Updates and Repository Delivery Windows

The README says the central GitHub repository, API, official mirror, and DNS service are updated daily. It gives approximate UTC delivery windows: about 19:05 to 19:15 for the central repository, 19:05 to about 19:20 for the API and search engine, 19:30 to about 19:35 for the official mirror, and 19:30 to about 19:40 for DNS. These schedules describe publication timing, not a guarantee that every client will have loaded the new entries immediately.

The repository is not archived, and its last push was on 2026-10-14. It also has no GitHub releases. That distinction matters for upgrades: operators receive list changes through the repository or service rather than through a documented release package. The README calls its list version `V2.3812.2026.10.03`, but it does not define a stable release process, migration guide, or compatibility policy for consumers.

A local hosts deployment therefore has maintenance work. An operator must decide when to download the replacement file, validate it, distribute it, and reload the relevant client. The README says files are updated daily but does not document an atomic update procedure, change log format, rollback procedure, or automation script. DNS users avoid some of this work by delegating updates to the service, at the cost of trusting its availability and administration.

UHB Limits: Coverage Gaps, False Positives, and Unsupported Claims

The first limitation is architectural. A hosts file can block only entries that the client resolves through that mapping, while UHB's DNS service can block only traffic that uses those resolvers. Applications with their own embedded DNS behavior, encrypted transport to an unlisted destination, or policies outside the supplied domain and IP data are not addressed by the documented mechanism. The README does not claim to inspect traffic, remove malware, patch software, detect ransomware behavior, or replace antivirus software, so it should not be evaluated as if it performs those tasks.

The second limitation is list quality. UHB combines data from multiple sources and describes regular testing and daily merging, but the README does not publish the source inventory, validation criteria, expiry policy, false-positive handling, or an independent reproduction method for the displayed counts. A large list is not equivalent to a proven high-accuracy list. Operators may need to watch for blocked software update hosts, authentication services, advertising systems, and internal network names.

The third limitation is deployment control. DNS is convenient, but it moves policy enforcement outside the local hosts file. The README states that the resolvers do not log, yet it does not explain operational ownership, retention of DNS queries, behavior during network failures, or how users submit and track individual exceptions. This makes UHB more suitable for a controlled evaluation than for an unattended production deployment without review.

UHB Compared With DNS Filtering and Smaller Hosts Files

The practical alternative is a conventional DNS filtering service that organizes block categories, provides an administrator interface, and exposes category or exception controls. The difference is not simply block count. UHB's documented selling point is a very large unified dataset delivered as raw files or through its two named resolvers. A conventional filtering service may provide more visible policy management, but that is a property of that class of service rather than a claim about any particular unnamed product.

A smaller hosts file is the other alternative. It is easier to inspect, less expensive for constrained devices to parse, and gives the operator direct control over each entry. It will generally cover fewer destinations, so it is better suited to a limited, reviewed set of blocked names than to broad network-wide filtering. UHB explicitly says its files may be too large for some devices, which is why it offers DNS access.

For a router or family network, the choice is between centralized DNS and per-device files. For a single computer, a reviewed local file avoids an external DNS dependency. For an administrator who needs category subscriptions, audit interfaces, or managed exceptions, UHB's documentation would need to supply more operational detail before it could replace a full DNS filtering console.

UHB Licensing, Reporting Routes, and Upgrade Boundaries

The repository is distributed under the MIT license. That identifies the license associated with the project, but the README does not provide legal guidance about how a deployment should handle attribution, redistribution, or modifications. Organizations should inspect `LICENSE.md` before copying large list files into an internal distribution system or modifying them.

UHB also separates reporting by purpose. The README directs general questions and discussions to the main repository, infrastructure matters to `dev-center`, list additions and removals to `dev-center`, and domain or IP additions and removals to the `blacklist` and `whitelist` repositories. This is useful because a false-positive request is not treated as an ordinary infrastructure question. The documentation does not promise a response time, review standard, or guaranteed turnaround for a correction.

The practical upgrade boundary is the format and destination system. A Unix file should not be assumed to be interchangeable with the CRLF/DOS `hosts.windows` file, and `hosts.deny` is a different artifact from `superhosts.deny`. UHB's MIT license and daily update process make redistribution possible, but the missing rollback documentation means an operator still needs a verified local copy before replacing a production file.

Editorial conclusion

Adopt UHB when centralized DNS or hosts-file blocking fits your network and you accept the operational trade-offs of an external list service. Do not treat it as a complete malware defense. Before deployment, verify the current list files or DNS availability, confirm that blocked entries do not interfere with required services, and review the MIT license and reporting routes.

Frequently asked questions

Official sources

1. Issues
2. License: MIT
3. README
4. Ultimate-Hosts-Blacklist/Ultimate.Hosts.Blacklist on GitHub