2 servers many clients with data

package main
// This is a parot server
// January 2018, JCA, IUT, University of Nnantes
// VERSION QUI RENVOIE UN NOMBRE EN FONCTION DE CE QU'IL Y A DANS LA MAP

import (
    "net"  // for net/socket resources
    "os"   // for OS resources
    "fmt"  // general formatting
    //"strconv" // Convert str to int or int to
    // "bufio" // intput output package
    )

//--------------------------------------------
func interactWithClient(commSock net.Conn) {
    myMap := map[string]string{
        "1":"Salut",
        "2":"Comment va ?",
        "3":"Bien et toi ?",
        "4":"Travail terminé !",
        "42":"BIEN JOUE !",
    }
    // send a Agreement msg to the client
    writelen, err := commSock.Write([]byte("Serv ACK! > Ready to receive\n"))
    if err != nil {
        fmt.Fprintf(os.Stderr, "Could not write to socket: %s\n", err)
    } else {
        fmt.Printf("Wrote %d bytes to socket\n", writelen)
    }

    for ;; { // Server loop to interact with the client
        buf := make([]byte, 256) // for buffering // but redecl :-(
        bufLen, err := commSock.Read(buf) // try a read  buffer from the Sock
        if err != nil {
            fmt.Fprintf(os.Stderr, "Error when reading from socket: %s\n", err)
            return
        }
        if bufLen == 0 {
            fmt.Printf("Connection closed by remote host\n")
            return
        }
        fmt.Printf("Length of read buffer = %d\n",bufLen)
        buf = buf[:bufLen-2]  // this is to ignore the 2 '\n', counting from 0
        fmt.Printf("Client at %s says %s \n", commSock.RemoteAddr(), buf)
        // prepare the response
        resp := ""
        num := string(buf)      // Cast the buff to string
        if myMap[num] == "" {
            resp = "ANS> No value matches"+"\n"
        } else {
            resp = "ANS>"+myMap[num]+"\n"
        }
        // send a 'response' to the client via the same connScock
        writtenLen, err := commSock.Write([]byte(resp))
        if err != nil {
           fmt.Fprintf(os.Stderr, "Could not write to socket: %s\n", err)
           } else {
           fmt.Printf("Wrote %d bytes to socket\n", writtenLen)
       }
   }//for
}

func listenForClients(ip string, port string) {
    sockListener, err := net.Listen("tcp", ip + ":" + port)
    if err != nil {
        fmt.Fprintf(os.Stderr, "Could not listen on socket: %s\n", err)
        return
    }
    for ;;{     // Allows to accept many clients
        // try to accept clients on the connection sockect => communic socket
        commSock, err := sockListener.Accept()  // wait until a Dial from a client
        if err != nil {
            fmt.Fprintf(os.Stderr, "Could not accept connection on socket: %s\n", err)
            return
        }
        resp := "BONJOUR, Vous êtes sur le serveur " + ip + ":" + port + "\n"
        _, _ = commSock.Write([]byte(resp))
        if port == "2056"{
            interactWithClient(commSock) // interact wih a client in case of a 'Dial'. Launch and continue the for loop
        } else {
            go interactWithClient(commSock) // interact wih a client in case of a 'Dial'. Launch and continue the for loop
        }
    }
}

//------------------------------
func main() {
    // attempt to create a connection sock
    // listening at a port of a machine : localhost:port


    go listenForClients("172.28.11.42","2056")
    listenForClients("172.28.11.42","2057")


}

//-----------------------------
//  to run the server after compilation, from an xterm  : ./sockServer_1
//
//  to interact from client side : telnet localhost 2056
//----------------------------