PlayerShooting.cs

using UnityEngine;
using System.Collections;
using UnityEngine.Networking;

public class PlayerShooting : NetworkBehaviour {

    public int Damage = 25;
    public Camera cameraTR;
    private RaycastHit hit;
    private Ray ray;

    void Update ()
    {
        if (Input.GetKeyDown (KeyCode.Mouse0))
        {
            Shoot();
        }
    }
    void Shoot()
    {
        ray = cameraTR.ScreenPointToRay (Input.mousePosition);
        if (Physics.Raycast (ray, out hit, 1000))
        {
            if(hit.transform.tag == "Player")
            {
                string id = hit.transform.name;
                CmdShoot(id, Damage);
            }
        }
    }
    [Command]
    void CmdShoot(string Id, int dmg)
    {
        GameObject go = GameObject.Find (Id);
        go.GetComponent<PlayerInfo> ().GetDamage (dmg);
    }
}