TCPware V5.9 Management Guide

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Chapter 29

Tunneling DECnet over IP


This chapter describes how to set up and manage the TCPware for OpenVMS feature that supports tunneling of DECnet over IP-based networks.

DECnet over IP support provides tunneling of DECnet data link layer packets over a TCP/IP connection between two OpenVMS systems. Both systems must run TCPware for OpenVMS. This feature lets you establish a DECnet line and circuit between two OpenVMS systems connected to each other over a TCP/IP network.

Note! This feature is intended for DECnet Phase IV. There is no need to use it with DECnet/OSI (DECnet Phase V). Instead, configure DECnet/OSI to run over TCP/IP as described in the DECnet/OSI documentation. No special TCPware configuration is required.

Figure 29-1 shows an example of one of the many ways that you can use tunneling DECnet over IP. The example shows two DECnet areas connected together through a DECnet over IP tunnel. The shaded nodes, ALPHA and THRUSH, run both DECnet and TCPware for OpenVMS. The other nodes may run only DECnet.

Figure 29-1 Tunneling DECnet over IP Undisplayed Graphic

From the system manager's point of view, DECnet over IP support consists of:

CNFNET prompts that configure and start up DECnet over IP tunnels

Options to STARTNET and SHUTNET that start and shut any DECnet over IP tunnels

NETCU SHOW DNIP command to show information about any DECnet over IP tunnels

Device driver DNIPDRIVER

DECnet over IP Lines

To use DNIP lines, you must install a DECnet routing license on the system, unless the DNIP line is the only DECnet line on the system.

DECnet over IP Tunnels

You invoke DECnet over IP configuration in one of two ways:

During TCPware for OpenVMS configuration with CNFNET, by answering YES at the Do you want to configure DECnet over IP tunnels? prompt

At any time after configuration, by invoking just the DECnet over IP portion of configuration by entering this command: @TCPWARE:CNFNET DNIP

CNFNET prompts for the following information for each DECnet over IP tunnel:

DECnet line name (for example, DNIP-0-0)

Remote host name or IP address

Port number of the tunnel on the local host

Port number of the tunnel on the remote host (this is optional)

The port number is the TCP port number at which the system establishes DECnet over IP connections. You can reuse this same port number for all tunnels on a single system, and for all systems in your network. Note that the default value (64215) has no special significance, it is simply a "random" TCP port that any other service on your system is unlikely to use.

See the Installation & Configuration Guide, Chapter 4, Configuring the TCP/IP Services, the Configure DECnet over IP Tunnels section.

When you start TCPware, it automatically:

Starts up the configured DECnet over IP tunnels.

Performs DECnet configuration of the associated DECnet lines and circuits.

You need to perform all other DECnet network management through NCP, for example: defining DECnet node numbers and names.

Starting and Stopping

Normally, all configured DECnet over IP tunnels start when you start TCPware for OpenVMS. If for any reason you want to shut down and later restart, only the DNIP tunnels (and not all of TCPware for OpenVMS), use the following commands:

To stop all DECnet over IP tunnels configured on your host: @TCPWARE:SHUTNET DNIP

To start all DECnet over IP tunnels configured on your host: @TCPWARE:STARTNET DNIP


Use the SHOW DNIP command in the Network Control Utility (NETCU) to show information about the currently configured DECnet over IP tunnels.

See the SHOW DNIP command of the NETCU Command Reference.


If you get the following message when configuring the DECnet over IP tunnel, you may have entered a host domain name instead of an IP address. It is possible that your HOSTS. file or DNS could not resolve the domain name. Try re-specifying the host address as an IP address:

%DNIP-E-INVIA, invalid internet address

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