[wereHamster]

On mac you can always use little snitch (https://www.obdev.at/products/littlesnitch/index.html) to reliably block outgoing connections. No need to muck around with environment variables, and you don't have to guess which domains dotnet uses, little snitch will tell you, even if they change them in the future.

[simooooo]

I'll just set the environment variable thanks.

[wereHamster]

Haha, who makes sure that dotnet actually honors the env variable? It could still connect to servers and exfiltrate data.

OTOH nobody gets around a firewall which blocks all outgoing connections ;)