DECnet is a proprietary LAN and WAN protocol that has become a standard within the OpenVMS world. DECnet implements many of the TCP/IP protocols, and most of those predate TCP/IP. For instance, the asynchronous serial communications (SLIP in the TCP/IP world) called digital data communications message protocol (DDCMP) has been supported by DECnet for at least 20 years. DECnet security is far superior to TCP/IP even today; however, because DECnet is proprietary, it has never been very popular.
The newest package is called DECnet-Plus (sometimes called DECnet/OSI or DECnet V). It is set up with a script called NET$CONFIGURE and managed with the Network Command Language (NCL) command. When the system is booted, this version of DECnet starts automatically if it is installed.
A partial display of the set up script is as follows:
$ @sys$manager:net$configure basic Copyright (c) Digital Equipment Corporation 1993, 1996. All rights reserved. DECnet-Plus for OpenVMS BASIC network configuration procedure This procedure will help you create or modify the management scripts needed to operate DECnet on this machine. You may receive help about most questions by answering with a question mark '?'. You have chosen the BASIC configuration option. This option enables you to quickly configure your system by answering a few questions and using most of the default answers. If you would rather do some specific tailoring of your system's network configuration, you should invoke NET$CONFIGURE.COM with the ADVANCED configuration option, ie: @SYS$MANAGER:NET$CONFIGURE ADVANCED Do you want to continue? [YES] : Enter the directory services to use on the system [LOCAL,DECDNS,DOMAIN] : Enter the full name for directory service LOCAL : LOCAL:.ELMER Enter the full name for directory service DECDNS : ACME:.WABBIT.ELMER Enter the fully qualified host name for DNS/BIND : ELMER.WABBIT.ACME.EDU What type of node (Endnode or Router)? [ENDNODE] : Type of routing node (L1 or L2)? [L1] : What is the synonym name for this node? [ELMER] : You have installed wide area device support, but it has not been configured. You may configure it now if you want. Do you want to configure Wide Area devices? [YES] : Are you satisfied with the answers you have given [Y] ?
Based on this dialog, NET$CONFIGURE builds an NCL script and then executes NCL using that data as input to initialize the DECnet database. Of course, the manager can enter the necessary operations interactively using NCL commands as well. The script is a labor-saving device.
The older version, DECnet IV, is still popular and supported. It is set up and managed with commands that are nearly the same as those of DECnet-Plus. The initialization script is called NETCONFIG (notice the $ is missing), and it is managed with Network Control Program (NCP). When the system is booted, it is initialized with a line in SYSTARTUP_VMS, @SYS$STARTUP:STARTNET.
The configuration script display is as follows:
$ @SYS$MANAGER:NETCONFIG.COM DECnet for OpenVMS network configuration procedure This procedure will help you define the parameters needed to get DECnet running on this machine. You will be shown the changes before they are actually executed, in case you wish to perform them manually. What do you want your DECnet node name to be? : What do you want your DECnet address to be? : Do you want to operate as a router? [NO (nonrouting)]: The network object database file is SYS$COMMON:[SYSEXE]NETOBJECT.DAT;4. Do you want to purge the object database? [YES]: Do you want a default DECnet account? [NO]: Do you want a default account for the MAIL object? [YES]: Do you want a default account for the FAL object? [NO]: Do you want a default account for the PHONE object? [YES]: Do you want a default account for the NML object? [YES]: Do you want a default account for the MIRROR object? [YES]: Do you want a default account for the VPM object? [YES]: Do you want these commands to be executed? [YES]:
This dialog builds a script to be run by NCP to initialize the DECnet database.
To support the security of this product, two databases are supported. Associated with DECnet-Plus is a file called NET$PROXY.DAT, and with DECnet IV, it is called NETPROXY.DAT. Both are managed with AUTHORIZE to permit users and processes DECnet access.
For instance, first assume that users have accounts on two nodes (say LOON and KEITH). The two nodes are connected with DECnet, but the nodes are not clustered together. Now, to permit any user on the LOON node to access his or her account on the KEITH with DECnet, the following AUTHORIZE command would be entered on KEITH:
$ MCR AUTHORIZE UAF> ADD/PROXY LOON::"* */ DEFAULT
This permits any user logged in to LOON to perform DECnet operations such as the following:
$ COPY KEITH::ANYFILE.TXT NEWFILE.TXT $ TYPE KEITH::[.REPORTS]LISTFILE.DOC
The double-colon syntax signifies a node name, and directory syntax is also permitted. The manager would probably want to perform the same AUTHORIZE ADD/PROXY command on LOON as well to permit users to do symmetric operations.
DECnet syntax is recognized by any OpenVMS command that involves a file. DECnet is also recognized by several OpenVMS utilities (e.g., MOTIF, INITIALIZE/QUEUE, BACKUP, and EXCHANGE/NETWORK). MONITOR and SYSMAN are able to use DECnet to communicate between clustered nodes.