Nginx多层代理获取真实客户端IP

一般的应用都是通过Nginx来做为反向代理，并且Nginx还可能是多层的。如果想在内部服务里面获取最原始的客户端IP地址。则需要做一些配置

最外层Nginx

为了防止X-Forwarded-For头的伪造，可在最外层Nginx将X-Forwarded-For设置为真实IP$remote_addr。 $remote_addr是获取的是直接TCP连接的客户端IP（类似于Java中的request.getRemoteAddr()），这个是无法伪造的，即使客户端伪造也会被覆盖掉，而不是追加。

1    upstream innerservice {
2        server 192.168.12.33:9001;
3        server 192.168.12.34:9002;
4    }
5    server {
6        listen    9000;
7        server_name  192.168.12.22;
8        root         /usr/share/nginx/html;
9        include /etc/nginx/default.d/*.conf;
10        location / {
11            proxy_pass http://innerservice;
12            proxy_set_header Host $host:$server_port;
13            proxy_set_header X-Real-PORT $remote_port;
14            proxy_set_header X-Real-IP $remote_addr;
15            proxy_set_header X-Forwarded-For $remote_addr;
16        }
17    }

后续Nginx配置

1    upstream innerservice {
2        server 192.168.12.33:9001;
3        server 192.168.12.34:9002;
4    }
5    server {
6        listen    9000;
7        // xxx
8        location / {
9            proxy_pass http://innerservice;
10            proxy_set_header Host $host:$server_port;
11            proxy_set_header X-Real-PORT $remote_port;
12            proxy_set_header X-Real-IP $remote_addr;
13            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
14        }
15    }

Java中获取真实IP

1/**
2 * Description：客户端信息获取过滤器
3 */
4public class ClientContextFilter extends OncePerRequestFilter {
5
6    /**
7     * Nginx默认增加的IP地址头
8     */
9    public static final String HEADER_X_FORWARDED_FOR = "X-Forwarded-For";
10
11    /**
12     * 内部微服务之间调用增加的IP地址头
13     */
14    public static final String HEADER_X_REMOTE_USER_IP = "X-Remote-User-IP";
15
16    /**
17     * IP响应头的分割符号
18     */
19    private static final String IP_HEADER_DELIMITER = ",";
20
21    @Override
22    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
23        try {
24            String remoteUserIP = loadRemoteUserIP(request);
25            ClientContext context = new ClientContext();
26            context.setClientIP(request.getRemoteAddr());
27            context.setRemoteUserIP(remoteUserIP);
28            ClientContextHolder.setContext(context);
29            filterChain.doFilter(request, response);
30        } finally {
31            ClientContextHolder.clearContext();
32        }
33    }
34
35    private String loadRemoteUserIP(HttpServletRequest request) {
36        String xForwardedHeader = request.getHeader(HEADER_X_FORWARDED_FOR);
37        // 先尝试从X-Forwarded-For获取
38        if (xForwardedHeader != null && xForwardedHeader.trim().length() > 0) {
39            String[] ips = xForwardedHeader.split(IP_HEADER_DELIMITER);
40            return ips[0].trim();
41        } else {
42            // 尝试从内部自定义头上获取
43            String internalIPHeader = request.getHeader(HEADER_X_REMOTE_USER_IP);
44            if (null != internalIPHeader && internalIPHeader.trim().length() > 0) {
45                return internalIPHeader.trim();
46            } else {
47                return null;
48            }
49        }
50    }
51}

原理是在服务往后面传递的时候，定义一个自定义头，将真实IP放到这个header中。 后台服务可取两个IP地址

• request.getRemoteAddr() - 获取调用方服务的内网IP地址
• loadRemoteUserIP - 获取最源头的真实客户端IP地址