[WeidiDeng]

In 7151, net.KeepAliveConfig is used instead of KeepAlive. However, this made disabling keep alive impossible, as a negative value of Interval will just left the underlying socket option unchanged.

For now, disable keep alive when KeepAliveInterval is negative, when it's zero, a system dependent default is chosen automatically.

[WeidiDeng]

In 7157, whether net.KeepAliveConfig.Enable is true depend on if the ProbeInterval is positive because in that case, we use net.Dialer which willl handle keep alive for us. Namely, if net.KeepAliveConfig.Enable is false and KeepAlive is zero, a default value will be chosen. Though reverse proxy will use 30 seconds if not configured explicitly.

When listening, sometimes we don't use net.ListenConfig to listen, for example, socket activation. So keep alive is enabled by default as well.

[mohammed90]

Good catch!