3 ms·

Or in the UK it's the telephone number for the emergency services, so suggesting "I'll call the police on you!" to unwelcome traffic. More likely they just use

Or in the UK it's the telephone number for the emergency services, so suggesting "I'll call the police on you!" to unwelcome traffic. More likely they just used it because it's one end of the 3 digit range and a "proper" code would leak information to the unwelcome traffic about what they did to get blocked (making it easier to avoid). Apparently some services already use 000 for other purposes (TIL).

wongarsu 3y ago
And any new first digit for some theoretical protocol extension would use 6xx, so 999 is extra future-proof. Not that this is likely to ever matter, unless we introduce a status code category for "the interplanetary gateway is at fault" or something like that.