![[Contents]](FIGURE/CONTENT.GIF)
OpenTP1 Version 7 TP1/Client User's Guide TP1/Client/W, TP1/Client/P
![[Index]](FIGURE/INDEX.GIF)
![[Back]](FIGURE/FRONT.GIF)
![[Next]](FIGURE/AFTER.GIF)
TP1/Client includes functionality that fixes the receive port used to receive a connection establishment request from the server. This functionality is called the fixed receive-port facility.
This facility is used when TP1/Server requests establishment of a connection to TP1/Client through a firewall whose filter settings are specified to allow transmission to only a single specified receive port.
Before this facility can be used, a receive port must be specified for DCCLTCUPRCVPORT of the client environment definition.
The following shows the difference when the fixed receive-port facility is not used and when it is used.
For communication of responses to RPCs, no filtering is performed on the receive port. The OS automatically assigns a port as the TP1/Client RPC receive port.
The following figure shows how RPCs that use the scheduler direct facility are processed when the fixed receive-port facility is not used.
Figure 2-38 Processing when the fixed receive-port facility is not used (for RPCs that use the scheduler direct facility)
![[Figure]](FIGURE/ZU022800.GIF)
The port specified for DCCLCUPRCVPORT of the client environment definition becomes the receive port on which the communication of responses to RPCs is allowed. All other ports are filtered out. Accordingly, the firewall is able to block responses from TP1/Server to illegal service requests.
The following figure shows the processing of RPCs that use the scheduler direct facility when the fixed receive-port facility is used.
Figure 2-39 Processing when the fixed receive-port facility is used (for RPCs that use the scheduler direct facility)
![[Figure]](FIGURE/ZU022900.GIF)
Note that the fixed receive-port facility is not enabled in the following cases:
All Rights Reserved. Copyright (C) 2006, 2009, Hitachi, Ltd.