RDP Preread

When using the RDP protocol, this module allows extracting cookies, which are used for session identification and management, before making a load balancing decision.

When building from the source code, this module isn't built by default; it should be enabled with the ‑‑with‑stream_rdp_preread_module build option.

In packages and images from our repos, the module is included in the build.

Configuration Example

Binding to the Cookie-Issuing Server

This uses the learn mode of the sticky directive:

stream {

    rdp_preread on;

    upstream rdp {

        server 127.0.0.1:3390 sid=a;
        server 127.0.0.1:3391 sid=b;

        sticky learn lookup=$rdp_cookie create=$rdp_cookie zone=sessions:1m;
    }
}

Directives

rdp_preread

Syntax	rdp_preread on | off;
Default	rdp_preread off;
Context	stream, server

Controls extracting information from RDP protocol cookies during the preread stage. If the setting is on, its surrounding context will have the following variables populated.

Built-in Variables

The semantics of cookie values depend on the RDP protocol version.

$rdp_cookie

The entire cookie value.

$rdp_cookie_<name>

The value of the cookie field with the specified name.