48 IBM Tivoli Remote Control Across Firewalls
name of the Gateway Proxy which the Target is connected to. As the 
RC Controller Proxy must be installed on the same machine as the 
Gateway Proxy, the RC Target proxy is able to connect to this RC 
Controller Proxy and forward the Target request using the Gateway 
Proxy IP Address provided by the Endpoint Proxy. The RC Controller 
Proxy then uses the Target information stored in the first request to 
start a session with the Target.
The Remote Control session is now established. It is important to 
notice that once the session established, the Controller talks directly 
with the Target, but it’s not a peer-to-peer communication 
(Controller-Target) anymore, as the communication flow must always 
go through the Remote Control Proxies. 
The Target is listening on port defined in the rc_def_ports policy. 
On the Controller side, by default, the port is assigned by the 
communication stack. However, these ports could be easily changed 
by configuring the rc_def_ports Remote Control Policies. The RC 
Target Proxy and the RC Controller Proxy are listening on the port 
defined during the installation process. The port  specified in the 
rc_def_proxy policy must be the same as defined during the 
installation process of the RC Target Proxy. The configuration of 
these RC Proxies ports could be reviewed by editing the rcproxy.cfg 
configuration file. However, if you decided to change this port, you 
need to also review the rc_def_proxy policy. For more information 
about the RC Proxies configuration files, refer to 
IBM Tivoli Remote 
Control User’s Guide
, SC23-4842.
In the scenario depicted in Figure 1-8 on page 46, there are two 
firewalls separating the standard Tivoli environment from the distant 
Endpoints. To let the RC Target Proxy, which needs to be on the 
same network zone that the Controller, communicate with the RC 
Controller Proxy, which needs to be close to the Target, a second 
instance of a Relay is needed. Its role it just to forward the packet to 
the final destination between the different network zones. Multiple 
Relays could be chained to cross all multiple secure zones. The 
Relay is not a Remote Control Component, it is a Tivoli Firewall 
Security Toolbox one. In fact, one instance of the Relay is needed to 
manage network flow between the Endpoint Proxy and Gateway 
Proxy and another instance of the same Relay need to be installed 
on the same machine as the first Relay instance to manage the 
network flow between the Remote Control Proxies.
In order to implement the Remote Control session to us e Remote Control 
Proxies, the rc_def_proxy default policy method needs to be configured, for 
instance, as shown in Example 1-18.