再给大家一个国外的类。超级好的东西。呵呵。

/******************************************************************************************************************
*    Class:           Trace
*    Description:        Traces path of an ip packet with its respond time
*    Author:           Sanjay Ahuja
*    Date:           5/15/2002
*    Copyright?       ?2002, Sanjay Ahuja ([email protected]). Use it as you want till you leave my name intact
/******************************************************************************************************************/
using System;
using System.Net;
using System.Net.Sockets;
//ICMP constants
struct ICMPConstants
{
    public const int ICMP_ECHOREPLY= 0;       // Echo reply query
    public const int ICMP_TIMEEXCEEDED= 11;        // TTL exceeded error
    public const int ICMP_ECHOREQ=    8;       // Echo request query
    public const int MAX_TTL= 256;           // Max TTL
}
//ICMP header, size is 8 bytes