关于nginx重定向后端口问题

Question

场景：在第三方架设nginx反向代理，服务器在远程，第三方开放了8800端口

访问xx.xx.xx.xx:8800 出现302重定向 紧接着400 地址为xx.xx.xx.xx丢失了8800端口（就是转向默认的80端口）

如果手动加上8800端口就可以正常访问

附配置
server {

    listen       8800;
    server_name  localhost xxxxx;

    #charset koi8-r;

    #access_log  logs/host.access.log  main;

    location / {
        proxy_pass xxxxx;
        proxy_set_header Host $host:8800;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header REMOTE-HOST $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }

}

Answer 1

listen       8800;
server_name  localhost xxxxx;

#charset koi8-r;

#access_log  logs/host.access.log  main;

location / {
    #rewrite ^/(.*)$ http://xx.xx.xx.xx:80/;
    proxy_pass xxxxx;
    proxy_set_header Host $host;(去掉8800)
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header REMOTE-HOST $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}

Answer 2

listen 8800;

server_name  localhost xxxxx;

#charset koi8-r;

#access_log  logs/host.access.log  main;

location / {
    proxy_pass xxxxx;
}

Answer 3

配置没看到明显问题，nginx不会主动将请求重定向到80端口