# tested with: # sudo firewall-cmd --direct --add-rule ipv4 filter OUTPUT 0 -d -j DROP package main import ( "fmt" "net" "time" ) func main() { for i := 0; i < 30; i++ { time.Sleep(1 * time.Second) go func(count int) { t := time.Now() conn, err := net.DialTimeout("tcp", "google.com:80", 1*time.Second) duration := time.Now().Sub(t) fmt.Printf("%v: Duration=%v, conn=%v, err=%v\n", count, duration, conn, err) }(i) } }