Don't know anything about ZScaler but I use the peek and splice feature of squid to block/allow domains.
(you need to build custom debian packages for this). Of course, this only works as long as ESNI can be blocked. Tim. On Wed, 19 Jan 2022, Andreas Ames wrote:
Hello all, I am sitting behind a firewall, in my case esp. ZScaler. I am wondering, what the best way is to whitelist "deb.debian.org" for package management. Do I have to whitelist individually all mirror sites that back the CDN? If so, is there an up-to-date list of the hosts backing "deb.debian.org"? Offtopic: Do you know, whether services like ZScaler provide dedicated support for CDNs? Thanks in advance, Andreas