I can't think of anything that would warrant a 2GB receive buffer. The buffer should be sized so that the receiving program has a reasonable amount of time to d

I can't think of anything that would warrant a 2GB receive buffer. The buffer should be sized so that the receiving program has a reasonable amount of time to drain it before it becomes full. A large skylake VM in GCP can do 32 Gbps (lowercase b), so assuming worst conditions, a 2GB receive buffer would give the receiver 500ms to call recv(), which is a huge amount of time for something that should take microseconds, especially in the context of a client. Even if there was a specialized server that needed such a large receive buffer, it doesn't make sense to set the system-wide default so high.