Download Hostnames from Unusable CT Logs 📜


The data was obtained by parsing CT with modified software, which will be discussed below. I cannot guarantee the accuracy of the data, as it is possible that some data was lost due to a variety of factors, such as the data from Let's Encrypt Oak 2022. If you want to do passive data analysis and you want maximum accuracy for each specific CT, then I highly recommend that you use self-written software that has been tested to work correctly with CTs. You can always contact me using the contacts on the


Collecting the initial dataset for the project was a time-consuming task. As with any scanner, a significant amount of data is required, which can be provided by CTLs. However, due to rate limits and the large volume of certificates, downloading can take a considerable amount of time. Additionally, some companies may terminate their inactive CTLs. For instance, Cloudflare Nimbus 2022 is no longer publicly accessible, but it can still be downloaded from mirrors run by Google. I believe that even outdated archives can still hold value for research. I will not update this page, but I feel it is my duty to share this information with the world for archival purposes. The entire hostname list from inactive CTLs can now be accessed with a single button, instead of using modified software.

Data Format

All 7z archives contain a txt file with hostnames obtained using a slightly modified CaliDog/Axeman. All files are sorted from invalid hostnames, and since only inactive CTLs that are not/almost not updated have been downloaded, there is a good chance that the data is still current at the time of viewing this page. Hostnames are presented in plain text format, one hostname per line. Duplicate hostnames have not been removed from the data.


Thank you

CaliDog, for creating Axeman. Axeman served as the foundation for the software used in this project and saved countless hours of development time.
Google for creating and maintaining mirrors and, at the same time, archives of CT data. And for creating CT itself, of course.