TCP Check

package main

import (
        "log"
        "net"
)

func main() {
        var status string
        conn, err := net.Dial("tcp", "127.0.0.1:80")
        if err != nil {
                log.Println("Connection error:", err)
                status = "Unreachable"
        } else {
                status = "Online"
                defer conn.Close()
        }
        log.Println(status)
}

https://github.com/akutz/gotil/blob/master/gotil.go#L284