【linux-网络】4层转发方法-iptable以及nginx

1.背景

有时候远程或者某些业务需要做转发就会用到iptables或者nginx，或者ss都可以

根据自己的情况去适配。

2.方法：

1）iptables

-把linux内核转发功能打开

echo "net.ipv4.ip_forward=1" >> /etc/sysctl.conf

-出入转发：192.168.1.1:19100 -->10.22.0.5:9100

iptables -t nat -A PREROUTING -d 192.168.1.1 -p tcp -m tcp --dport 19100 -j DNAT --to-destination 10.22.0.5:9100

iptables -t -A POSTROUTING -d 10.22.0.5/32 -p tcp -m tcp --dport 9100 -j SNAT --to-source 192.168.1.1

2) nginx

-安装nginx：--一般现在新装版本nginx都在1.19以上，都含有--with-stream模块，手动编译的自行添加

yum -y install nginx

nginx -V

nginx version: nginx/1.20.1
built by gcc 4.8.5 20150623 (Red Hat 4.8.5-44) (GCC) 
built with OpenSSL 1.1.1k  FIPS 25 Mar 2021
TLS SNI support enabled
configure arguments: --prefix=/usr/share/nginx --sbin-path=/usr/sbin/nginx --modules-path=/usr/lib64/nginx/modules --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --http-client-body-temp-path=/var/lib/nginx/tmp/client_body --http-proxy-temp-path=/var/lib/nginx/tmp/proxy --http-fastcgi-temp-path=/var/lib/nginx/tmp/fastcgi --http-uwsgi-temp-path=/var/lib/nginx/tmp/uwsgi --http-scgi-temp-path=/var/lib/nginx/tmp/scgi --pid-path=/run/nginx.pid --lock-path=/run/lock/subsys/nginx --user=nginx --group=nginx --with-compat --with-debug --with-file-aio --with-google_perftools_module --with-http_addition_module --with-http_auth_request_module --with-http_dav_module --with-http_degradation_module --with-http_flv_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_image_filter_module=dynamic --with-http_mp4_module --with-http_perl_module=dynamic --with-http_random_index_module --with-http_realip_module --with-http_secure_link_module --with-http_slice_module --with-http_ssl_module --with-http_stub_status_module --with-http_sub_module --with-http_v2_module --with-http_xslt_module=dynamic --with-mail=dynamic --with-mail_ssl_module --with-pcre --with-pcre-jit --with-stream=dynamic --with-stream_ssl_module --with-stream_ssl_preread_module --with-threads --with-cc-opt='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -m64 -mtune=generic' --with-ld-opt='-Wl,-z,relro -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -Wl,-E'

配置：放到nginx.conf 里面就放到http上面，也可以在http上面加include指定路径。

stream {
        upstream tcp_proxy {
          hash $remote_addr consistent;
          server 10.22.0.5:9100;
          }
      server {
        listen 19100;
        proxy_connect_timeout 1s;
        proxy_timeout 10s;
        proxy_pass tcp_proxy;
     }
  }

启动服务器可；

检查端口是否起来