通常来说，大家获取用户IP地址常用的方法是：
string IpAddress = "";
if((HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"]!=null
&& HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] !=String.Empty) )
{
IpAddress=HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] ;
}
else
{
HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
}
事实上，上面的代码只试用与用户只使用了1层代理，如果用户有2层，3层HTTP_X_FORWARDED_FOR 的值是："本机真实IP,1层代理IP,2层代理IP,....." ，如果这个时候你的数据中保存IP字段的长度很小（15个字节），数据库就报错了。
实际应用中，因为使用多层透明代理的情况比较少，所以这种用户并不多。
获取用户真实IP的方法：
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text.RegularExpressions;
namespace Common
{
/// <summary>
/// IPAddress 的摘要说明
/// </summary>
public class IPAddress : System.Web.UI.Page
{
public static Int64 toDenaryIp ( string ip )
{
Int64 _Int64 = ;
string _ip = ip;
if ( _ip.LastIndexOf ( "." ) > - )
{
string[] _iparray = _ip.Split ( '.' );
_Int64 = Int64.Parse ( _iparray.GetValue ( ).ToString() ) * * * + Int64.Parse ( _iparray.GetValue ( ).ToString() ) * * + Int64.Parse ( _iparray.GetValue ( ).ToString() ) * + Int64.Parse ( _iparray.GetValue ( ).ToString() ) - ;
}
return _Int64;
}
/// <summary>
/// /ip十进制
/// </summary>
public static Int64 DenaryIp
{
get {
Int64 _Int64 = ;
string _ip = IP;
if ( _ip.LastIndexOf ( "." ) > - )
{
string[] _iparray= _ip.Split ( '.' );
_Int64 = Int64.Parse ( _iparray.GetValue ( ).ToString() ) * * * + Int64.Parse ( _iparray.GetValue ( ).ToString() ) * * + Int64.Parse ( _iparray.GetValue ( ).ToString() ) * + Int64.Parse ( _iparray.GetValue ( ).ToString() )-;
}
return _Int64;
}
}
public static string IP
{
get
{
string result = String.Empty;
result = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
if ( result != null && result != String.Empty )
{
//可能有代理
if ( result.IndexOf ( "." ) == - ) //没有"."肯定是非IPv4格式
result = null;
else
{
if ( result.IndexOf ( "," ) != - )
{
//有","，估计多个代理。取第一个不是内网的IP。
result = result.Replace ( " ", "" ).Replace ( "", "" );
string[] temparyip = result.Split ( ",;".ToCharArray() );
for ( int i = ; i < temparyip.Length; i++ )
{
if ( IsIPAddress ( temparyip[i] )
&& temparyip[i].Substring ( , ) != "10."
&& temparyip[i].Substring ( , ) != "192.168"
&& temparyip[i].Substring ( , ) != "172.16." )
{
return temparyip[i]; //找到不是内网的地址
}
}
}
else if ( IsIPAddress ( result ) ) //代理即是IP格式
return result;
else
result = null; //代理中的内容 非IP，取IP
}
}
string IpAddress = ( HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != null && HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != String.Empty ) HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] : HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"]; if ( null == result || result == String.Empty )
result = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
if ( result == null || result == String.Empty )
result = HttpContext.Current.Request.UserHostAddress;
return result;
}
}
//是否ip格式
public static bool IsIPAddress ( string str1 )
{
if ( str1 == null || str1 == string.Empty || str1.Length < || str1.Length > ) return false;
string regformat = @"^\\d{1,3}[\\.]\\d{1,3}[\\.]\\d{1,3}[\\.]\\d{1,3}$";
Regex regex = new Regex ( regformat, RegexOptions.IgnoreCase );
return regex.IsMatch ( str1 );
}
}
}