nginx loadbalancer tcp/udp syslog part 1

 http://nginx.org/en/docs/stream/ngx_stream_proxy_module.html#proxy_bind

https://docs.nginx.com/nginx/admin-guide/load-balancer/tcp-udp-load-balancer/#proxy_pass

Directives

Syntax:	proxy_bind address [transparent] | off;
Default:	—
Context:	stream, server

This directive appeared in version 1.9.2.

Makes outgoing connections to a proxied server originate from the specified local IP address. Parameter value can contain variables (1.11.2). The special value off cancels the effect of the proxy_bind directive inherited from the previous configuration level, which allows the system to auto-assign the local IP address.

The transparent parameter (1.11.0) allows outgoing connections to a proxied server originate from a non-local IP address, for example, from a real IP address of a client:

proxy_bind $remote_addr transparent;

In order for this parameter to work, it is usually necessary to run nginx worker processes with the superuser privileges. On Linux it is not required (1.13.8) as if the transparent parameter is specified, worker processes inherit the CAP_NET_RAW capability from the master process. It is also necessary to configure kernel routing table to intercept network traffic from the proxied server.