PMDF System Manager's Guide
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20.1 SMTP Over DECnet Channels

SMTP over DECnet channels are used to link systems running PMDF that are also connected via DECnet. These channels are comparable to the PhoneNet over DECnet channels described in the following section; the difference is that these channels use standardized SMTP protocols instead of the nonstandardized PhoneNet protocol. These channels can be used to communicate with systems that can speak SMTP over DECnet, notably other OpenVMS systems running PMDF.

SMTP over DECnet channels use unidirectional master and slave programs. The master program runs when PMDF has outgoing messages to send. The slave program runs in response to incoming DECnet requests.

On OpenVMS, DECnet SMTP channels can be generated by the automatic configuration generator.

20.1.1 Setting Up the Channel

Both PMDF and DECnet must be installed on both systems before a SMTP over DECnet channel can be set up. Once this is done, activating a SMTP over DECnet channel between them is quite straightforward as below.

20.1.1.1 Installing PMDF as a Known Object

PMDF must be installed as a known DECnet object on each system which is going to use a SMTP over DECnet channel.

First check what DECnet object numbers are currently in use and decide upon an unused one to assign to PMDF. Object numbers from 128 to 255 are available for customer use. The actual number used is irrelevant provided it is not used for any other purpose and all systems agree on the same number. Use the NCL command 


NCL> SHOW SESSION CONTROL APPLICATION * ALL CHARACTERISTICS
or the NCP command 


NCP> LIST KNOWN OBJECTS
to get a list of currently defined objects and their associated object numbers. Then choose an unused DECnet object number for PMDF's use.
On OpenVMS, you will also need to know the username of the PMDF account (usually just PMDF), to specify where pmdf_account is shown below. On a DECnet Phase IV system, you will additionally need to know the account's password, to specify where pmdf_password is shown below. These must match the local PMDF account for proper operation --- if the username or password for the PMDF account is changed, the DECnet database will have to be updated as well.

On a DECnet/OSI system, the DECnet object installation is performed using NCL.
On OpenVMS, use NCL as follows: 


$ RUN SYS$SYSTEM:NCL
NCL> CREATE SESSION CONTROL APPLICATION PMDFSMTP
NCL> SET SESSION CONTROL APPLICATION PMDFSMTP -
       ADDRESSES = {NAME = PMDFSMTP, NUMBER = xxx }, -
       OUTGOING PROXY = FALSE, -
       INCOMING PROXY = FALSE, -
       NODE SYNONYM = TRUE, -
       IMAGE NAME = PMDF_COM:dsmtp_slave.com, -
       USER NAME = "pmdf_account"



# ncl
ncl> create session control application pmdfsmtp
ncl> set session control application pmdfsmtp -
       addresses = {name = pmdfsmtp, number = xxx }, -
       outgoing proxy = false, -
       incoming proxy = false, -
       node synonym = true, -
       image name = "/pmdf/bin/dsmtp_slave", -
       user name = "pmdf"
Note the use of quotes to preserve lowercase, when case matters.
On a DECnet Phase IV OpenVMS system, the DECnet object installation is performed using the Network Control Program (NCP), as follows: 


$ RUN SYS$SYSTEM:NCP
NCP> DEFINE OBJECT PMDFSMTP -
            NUMBER xxx -
            FILE PMDF_COM:dsmtp_slave.com -
            USER pmdf_account -
            PASSWORD pmdf_password -
            ACCOUNT SYSTEM -
            PROXY NONE
NCP> SET    OBJECT PMDFSMTP -
            NUMBER xxx -
            FILE PMDF_COM:dsmtp_slave.com -
            USER pmdf_account -
            PASSWORD pmdf_password -
            ACCOUNT SYSTEM -
            PROXY NONE
The first command defines the PMDF object in the permanent DECnet database and the second defines the PMDF object in the volatile DECnet database.

You can have outgoing connections made by DSMTP channels identify themselves with the DECnet cluster alias instead of using the specific DECnet node name they happen to be running on. This is enabled by adding the NCL clause "OUTGOING ALIAS = TRUE" or the NCP clause "ALIAS OUTGOING ENABLED" to the commands shown above.

20.1.1.2 Adding the Channel to the Configuration File

The last step in setting up a SMTP over DECnet channel is to add the channels to the appropriate configuration files.

Note
The PMDF configuration utility, PMDF CONFIGURE, can be used to configure your system automatically with the appropriate DSMTP channels. When the PMDF configuration utility is used, all of the necessary configuration steps except for those described in Section 20.1.1.1 are done for you automatically. Consult the appropriate edition of the PMDF Installation Guide for instructions on using the configuration utility.)

A typical channel table entry for an SMTP over DECnet channel is of the form shown in Example 20-1; the corresponding rewrite rules are shown in Example 20-2.

Example 20-1 Sample SMTP Over DECnet Channel Block 

dsmtp_local single_sys smtp 
DSMTP-DAEMON 
ditmelb.oz.au     ditmb 
praxa.com.au      praxa

Note that while any channel name beginning with "dsmtp_" can be used with the master program (i.e., to send mail via a SMTP over DECnet link), the only channel that will be used with the slave program (i.e., to receive mail over a SMTP over DECnet link) is dsmtp_local.

Example 20-2 Rewrite Rules for Example 20-1 

praxa.com.au      $u@praxa.com.au 
ditmelb.oz.au     $u@ditmelb.oz.au

Here access is provided to two systems, ditmelb.oz.au and praxa.com.au. Their corresponding DECnet node names are ditmb and praxa. This format is analogous to that used in setting up the DECnet MAIL channel (channel d). As many systems as desired can be listed in the same channel block.

The daemon router keyword clause can be used to set up a point to point connection to a gateway through a SMTP over DECnet connection. See the documentation on TCP/IP gateway channels in Chapter 21 for additional information on how to set up a gateway channel.

After the configuration files are set up the channel should be ready for use.

20.1.1.3 Channel Option File

While it is extremely rare that controlling SMTP characteristics of an SMTP over DECnet channel is of interest, an option file can be used to control various such SMTP characteristics. See the list of options in Section 21.1.2.2; most of those options (those relating to the SMTP protocol itself, rather than specifically to TCP/IP transport issues) can also be applied to SMTP over DECnet channels.

Such an option file must be named x_option where x is the name of the channel, and stored in the PMDF table directory. Since the name of the channel is usually dsmtp_local, the option file is usually PMDF_TABLE:dsmtp_local_option. .

20.1.2 Network Service Logs

Once a slave channel program is successfully started, it will log eny errors or debugging output, to a normal PMDF channel log file, e.g., PMDF_LOG:dsmtp_local_slave.log .
On OpenVMS, however, since slave operations are initiated by DECnet directly, DECnet itself creates its own log files for slave operations. These log files appear in the default directory of the account under which the DECnet PMDFSMTP object runs; that account is normally the PMDF account hence normally the DECnet log files are in PMDF_ROOT:[log] on OpenVMS, and have the name netserver.log. Note that unlike other PMDF log files, these DECnet channel slave log files created directly by DECnet are not named according to the channel that created them.

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