Version 6 added DNS encryption and in principle we could filter lookups (similar to PiHole) at this level. That brings other issues, though: This filter is system-wide, so process-specific rules (and overrides) would not work. And results can be cached by mDNSResponder. So when a blocklist causes an issue, you may not be able to fix it by simply disabling the blocklist. But it's still something we consider.
I've been telling people about ya'll's DNS leaks for over a decade [3] — glad to finally hear back — most people won't believe me [0] until this flaw is demonstrated on their specific machine (easy enough). Those already using LittleSnitch will then typically set up better filtering (e.g. DNS white/blacklist, PiHole, et.alius).
And until the behavior is fixed, I will keep spreading the good word. Does the Linux version have this same flaw (i.e. backend requirements similar to Mac initial IP leak)?
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A very neat product (LittleSnitch), but I stopped using it solely for above reason [1]. IMHO, this flaw should be better documented in your installer/docs.
[0] e.g. they'll lament "there is no way the developer would allow that sort of leak/behavior!" Their denial is a helluvadrug
[1] I had a 5-user site license, IIRC. Shortly after purchasing, I discovered above leakage so stopped using entirely [v3 user 33TEWP20B0-724KY-5XE522FEAC [2]]
[2] Go ahead and blacklist/cancel the above registration (it's a manyyearsold version, barely used) – my current mailing address is in my user profile (no longer use email/phone). Would love to help/feedback to make your product better. Would also love a refund (all these years later, on principle)
[3] e.g: <https://news.ycombinator.com/item?id=35363343> (/hn/2023)
Please see my response to OD [I presume /u/littlesnitch is OD representative]. Nobody is disputing their "greatness" — I'm just criticizing a flaw in their approach to domain name filtering.
Hopefully OD will refund my original license (unused for many many many years, after I discovered this flaw). That would be good, in principle; good business. Hopefully OD will be more forthcoming in this vulnerability (or better disclose it) — or better yet: fix the unbelievable behavior.