What is a reverse proxy?

A Reverse Proxy is an intermediary between a public network and a set of private servers; which is responsible for managing service requests from one or more external computers. These work by manipulating HTTP requests that are sent by various computers; in a process in which requests are attended to and at the same time they manipulate the presentation of these services to avoid compromising critical information from the group of private servers where they are requested.

Diagram:

Taking advantage of the scenario in the previous post where we set up a haproxy cluster, we are going to implement our reverse proxy.

HAproxy High Availability Cluster on Red Hat 7

We make a backup of our initial configuration:

cp /etc/haproxy/haproxy.cfg /etc/haproxy/haproxy.cfg-bck

Configuramos el haproxy para realizar el balanceo al puerto del SFTP, en mi caso estoy empleado el 9022 para el servicio de SFTP.
cat /etc/haproxy/haproxy.cfg
global
maxconn 4096

daemon

defaults

timeout connect 5000

timeout client 50000

timeout server 50000
listen sftp

bind 172.20.0.12:9022

mode tcp

option tcplog

balance leastconn

server SFTP01 10.150.6.144:9022 check

server SFTP02 10.150.6.145:9022 check

We configure iptables to perform a NAT

iptables -t nat -A POSTROUTING -s 10.150.6.129/25 -j SNAT –to 10.150.6.144

iptables -t nat -A POSTROUTING -s 10.150.6.129/25 -j SNAT –to 10.150.6.145

We enable forwarding

echo 1 > /proc/sys/net/ipv4/ip_forward

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

We restart the cluster service

pcs resource restart

We try to connect using the public IP:

sftp sftp@<ip publica> 9022

All the best

:wq!