经过代理或者代理服务器以后,由于在客户端和服务之间增加了中间层,因此服务器无法直接拿到客户端的IP,服务器端应用也无法直接通过转发请求的地址返回 给客户端。但是在转发请求的HTTP头信息中,增加了X-FORWARDED-FOR信息,用以跟踪原有的客户端IP地址和原来客户端请求的服务器地址。 例如,当我们访问http://www.xxx.com/index.jsp/时,其实并不是我们浏览器真正访问到了服务器上的index.jsp文件,而是先由代理服务器去访问http://192.168.1.110:2046/index.jsp,代理服务器再将访问到的结果返回给我们的浏览器,因为是代理服务器去访问index.jsp的,所以index.jsp中通过request.getRemoteAddr()的方法获取的IP实际上是代理服务器的地址,并不是客户端的IP地址。
下面的方法在只有一级代理的情况下,可以保证获得客户端的真实IP地址:
- public String getIpAddr(HttpServletRequest request) {
- String ip = request.getHeader("x-forwarded-for");
- if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
- ip = request.getHeader("Proxy-Client-IP");
- }
- if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
- ip = request.getHeader("WL-Proxy-Client-IP");
- }
- if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
- ip = request.getRemoteAddr();
- }
- return ip;
- }
可是,如果通过了多级反向代理的话,X-Forwarded-For的值并不止一个,而是一串Ip值,究竟哪个才是真正的用户端的真实IP呢?答案是取X-Forwarded-For中第一个非unknown的有效IP字符串。
如:X-Forwarded-For:192.168.1.110, 192.168.1.120, 192.168.1.130, 192.168.1.100
用户真实IP为: 192.168.1.110
程序实现如下:
- // 获取请求主机IP地址,如果通过代理进来,则透过防火墙获取真实IP地址
- public String getIpAddr(HttpServletRequest request) {
- String strClientIp = request.getHeader("x-forwarded-for");
- log.info("All the IP address string is: " + strClientIp);
- if(strClientIp == null || strClientIp.length() == 0 ||"unknown".equalsIgnoreCase(strClientIp))
- {
- strClientIp = request.getRemoteAddr();
- }else{
- StringList ipList = new StringList();
- BusiAcceptAction.SplitsString(strClientIp, ',' , ipList); // 拆分字符串,可直接用String.plit方法
- String strIp = new String();
- for(int index = 0; index < ipList.size(); index ++)
- {
- strIp = (String)ipList.get(index);
- if(!("unknown".equalsIgnoreCase(strIp)))
- {
- strClientIp = strIp;
- break;
- }
- }
- }
- return strClientIp;
- }
转自 http://blog.csdn.net/foamflower/archive/2009/10/29/4744862.aspx
像移动网关一样,iisforward这个ISAPI过滤器也会对request对象进行再包装,附加一些WLS要用的头信息。这种情况下,直接用request.getRemoteAddr()
是无法取到真正的客户IP的。
实际的iisforward附加头如下:
WL-Proxy-Client-IP=211.161.1.239
Proxy-Client-IP=211.161.1.239
X-Forwarded-For=211.161.1.239
WL-Proxy-Client-Keysize=
WL-Proxy-Client-Secretkeysize=
X-WebLogic-Request-ClusterInfo=true
X-WebLogic-KeepAliveSecs=30
X-WebLogic-Force-JVMID=-327089098
WL-Proxy-SSL=false
综上,正确作法如下:
private String getIpAddr() {
String ipAddress = null;
//ipAddress = this.getRequest().getRemoteAddr();
ipAddress = this.getRequest().getHeader("x-forwarded-for");
if(ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
ipAddress = this.getRequest().getHeader("Proxy-Client-IP");
}
if(ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
ipAddress = this.getRequest().getHeader("WL-Proxy-Client-IP");
}
if(ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
ipAddress = this.getRequest().getRemoteAddr();
if(ipAddress.equals("127.0.0.1")){
//根据网卡取本机配置的IP
InetAddress inet=null;
try {
inet = InetAddress.getLocalHost();
} catch (UnknownHostException e) {
e.printStackTrace();
}
ipAddress= inet.getHostAddress();
}
}
//对于通过多个代理的情况,第一个IP为客户端真实IP,多个IP按照','分割
if(ipAddress!=null && ipAddress.length()>15){ //"***.***.***.***".length() = 15
if(ipAddress.indexOf(",")>0){
ipAddress = ipAddress.substring(0,ipAddress.indexOf(","));
}
}
return ipAddress;
}