[http] HTTP client timeout and server timeout

There's many forms of timeout, are you after the connection timeout, request timeout or time to live (time before TCP connection stops).

The default TimeToLive on Firefox is 115s (network.http.keep-alive.timeout)

The default connection timeout on Firefox is 250s (network.http.connection-retry-timeout)

The default request timeout for Firefox is 30s (network.http.pipelining.read-timeout).

The time it takes to do an HttpRequest depends on if a connection has been made this has to be within 250s which I'm guessing you're not after. You're probably after the request timeout which I think is 30,000ms (30s) so to conclude I'd say it's timing out with a connection time out that's why you got a response back after ~150s though I haven't really tested this.