1）如下测试，不设置 proxy_set_header
Nginx 配置：
upstream test {
server 192.168.1.123:9099;
server 192.168.1.123:58080;
}
server {
listen 5800;
server_name 192.168.1.123;
root /usr/share/nginx/html;
include /etc/nginx/default.d/*.conf;
location / {
proxy_pass http://test;
}
测试jsp 想获取客户端IP、客户端port、代理服务器IP、代理服务器port
<%@page contentType="text/html; charset=UTF-8" trimDirectiveWhitespaces="true"%>
<%
String scheme = request.getScheme();
String serverName = request.getServerName();
String remoteName = request.getRemoteAddr();
String realIP = request.getHeader("X-Forwarded-For");
String realIP2 = request.getHeader("X-Real-IP");
String Host = request.getHeader("Host");
int port = request.getServerPort();
int portR = request.getRemotePort();
String requestURIC1 = scheme+"://"+realIP+":"+portR;
String requestURIC2 = scheme+"://"+realIP2+":"+portR;
String requestURIC3 = scheme+"://"+remoteName+":"+portR;
String requestURI = scheme+"://"+serverName+":"+port;
%>
其中：
客户端地址1:<%=requestURIC1 %>
客户端地址2:<%=requestURIC2 %>
客户端地址3:<%=requestURIC3%>
服务器地址1:<%=requestURI%>
服务器地址2:<%=Host%>
测试结果
客户端地址1:http://null:58828
客户端地址2:http://null:58828
客户端地址3:http://192.168.1.123:58828
服务器地址1:http://test:80
服务器地址2:test
Nginx日志
192.168.1.177 -20508---5800 [25/Aug/2016:16:34:13 +0800] "GET /docs/test.jsp HTTP/1.1" 200 223 "
其中客户端IP不能获取到，而通过request.getRemoteAddr();
获取的IP是代理服务器IP，而不是客户端IP，而在nginx中$remote_addr变量的值是客户端的IP，可见remoteaddr没有传递。
而server_port值也不对，当前值为5800，当前打印出的是80。
而当前代理为http://test 所有通过host得到的是test。
客户端port也获取不到值为20508，可传给应用的是58828
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2）如下测试，设置 proxy_set_header
Nginx 配置：
upstream test {
server 192.168.1.123:9099;
server 192.168.1.123:58080;
}
server {
listen 5800;
server_name 192.168.1.123;
root /usr/share/nginx/html;
include /etc/nginx/default.d/*.conf;
location / {
proxy_pass http://test;
proxy_set_header Host $host:$server_port;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Real-PORT $remote_port;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}
测试页面改成：
<%@page contentType="text/html; charset=UTF-8" trimDirectiveWhitespaces="true"%>
<%
String scheme = request.getScheme();
String serverName = request.getServerName();
String remoteName = request.getRemoteAddr();
String realIP = request.getHeader("X-Forwarded-For");
String realIP2 = request.getHeader("X-Real-IP");
String Host = request.getHeader("Host");
int port = request.getServerPort();
int portR = request.getRemotePort();
String portR2 = request.getHeader("X-Real-Port");
String requestURIC1 = scheme+"://"+realIP+":"+portR;
String requestURIC2 = scheme+"://"+realIP2+":"+portR;
String requestURIC3 = scheme+"://"+remoteName+":"+portR;
String requestURI = scheme+"://"+serverName+":"+port;
%>
其中：
客户端地址1:<%=requestURIC1 %>
客户端地址2:<%=requestURIC2 %>
客户端地址3:<%=requestURIC3%>
服务器地址1:<%=requestURI%>
服务器地址2:<%=Host%>
客户端port2:<%=portR2%>
客户端地址1:http://192.168.1.177:21548
客户端地址2:http://192.168.1.177:21548
客户端地址3:http://192.168.1.123:21548
服务器地址1:http://192.168.1.123:5800
服务器地址2:192.168.1.123:5800
客户端port2:20604
nginx日志：
192.168.1.177 -20604---5800 [25/Aug/2016:16:38:42 +0800] "GET /docs/test.jsp HTTP/1.1" 200 275 "-" "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.106 Safari/537.36" "-"
除request.getRemoteAddr();获取的值不对外，其他值都是对的。
getRemoteAddr获取的是代理的请求地址。
因重定义了host,所以test值被改写成代理服务器IP。
因重定义了 X-Real-PORT-并传递$remote_port，客户端port也获取正确了。
