Hundreds of outbound connections, and a clear answer at every limit

A sandbox of an account that keeps a top-up now holds 512 outbound connections open at once for each vCPU, up to 4,096, where every sandbox held 64. In a test, 500 HTTPS connections opened at once from a 1 vCPU sandbox all connected, where 436 of them were reset before. New connections a second (20, after a first 128 at once) and new hosts a minute (120) stay as they were for every sandbox; past them a connection waits its turn instead of being reset. Past any limit a connection gets 503 with the limit in X-Runtime-Egress, and the account event sandbox.network.limited says which limit, at most once an hour. GET /v1/sandboxes/{id}/network shows a sandbox's limits. Accounts without a kept top-up keep 64. See the sandbox environment.