Novell MHS channels are used to convert messages between the RFC 822 and MIME message formats used by PMDF and the SMF (Standard Message Format) V70 format used by Novell MHS. PMDF can also interoperate with SMF V71 (see below). The Novell MHS channel programs combined with some mechanism to transfer files between systems produces an effective gateway between PMDF and Novell MHS.

SMF-70 is the message format used by Novell MHS version 1.5 in both the Network (1.5N) and Personal (1.5P) products. SMF-71 is the format used by Novell's newer Global Messaging products. PMDF will accept either format. Given the predominance of MHS 1.5 in the marketplace, PMDF generates SMF-70 format messages.

The Novell MHS channel programs attempt to convert as much of MIME as possible to compatible Novell MHS formats. However, limitations in Novell MHS make a complete conversion impossible, so in some cases the conversion will be limited in scope. In particular, Novell MHS is incapable of handling nested multipart structures, so any sense of nested structure is lost in the conversion process.

PMDF's Novell MHS channels perform all the functions of a Novell MHS gateway and appear to Novell MHS as a gateway despite the fact that the channels reside on a separate and independent system.

Note that Novell MHS is purely a message handling system. It includes no user agent. There are numerous Novell MHS compatible user agents available from third parties. These include Beyond's BeyondMail, Da Vinci's eMAIL, and Lantec's XPost among others.

38.8.1 Related Novell Documentation

38.8.2 Telling MHS About PMDF

Use the MHS Directory Manager to define PMDF^b as a gateway if you have not already done so. (The following commands are valid for MHS 1.5, but can differ for different versions of MHS.) While logged in as the MHS administrator, run the MHS Directory Manager (usually \MHS\EXE\MHS.EXE) and, select "Manage Directories", then select "routes to workgroups, hosts, and gateways", then select "Add entry" and "Define a gateway" or "Modify entry" if it had been defined already, then you are on the "A GATEWAY" screen, which should look like:

Host name: PMDF Description: Gateway to VMS or whatever Gateway version: 70 Gateway commands:

After exiting the Directory Manager, make sure the gateway subdirectories IN, IPARCEL, OUT, OPARCEL) in MHS are created; these should have been created by the MHS Directory Manager when you defined the gateway for PMDF in the earlier step.

Make sure you have a PC running the MHS Connectivity Manager. The Connectivity Manager is the program which will move messages to the PMDF's gateway subdirectories for PMDF to pick up, and it will also move messages into MHS from the gateway subdirectories in which PMDF had deposited messages.

38.8.3 Telling PMDF About MHS

1. pmdf.cnf, created by the PMDF configuration utility.
2. lan.rules, created by the PMDF-LAN configuration utility.
3. lan.chans, created by the PMDF-LAN configuration utility.
4. mhs_local_option, created by the PMDF-LAN configuration utility.
5. pc_post.com (OpenVMS) or pc_post (UNIX), created by the PMDF-LAN configuration utility.

38.8.3.1 Creating or Editing lan.chans

mhs_local master defragment charset8 ibm437 mhs-domain-name

mhs-domain-name should be a valid domain name that is reserved for use by the Novell MHS channel. One possible choice is to prepend the official local host name with "mhs.". For example, in the domain example.com, a reasonable domain name for the Novell MHS channel might be mhs.example.com and the channel entry would then appear as

mhs_local master defragment charset8 ibm437 mhs.example.com

The master keyword enables the normal PMDF periodic delivery jobs to check for the existence of the export file to be processed. It should be omitted if you chose to use pc_post.com (OpenVMS) or pc_post (UNIX) or your own procedure to pick up mail from the PC. See Section 38.2.2 for more details.

The defragment keyword tells PMDF to reassemble any fragmented MIME messages before sending them to Novell MHS.

The charset8 ibm437 tells PMDF that Novell MHS is using the IBM code page 437 character set.

38.8.3.2 Creating or Editing lan.rules

mhs $U%mhs.example.com mhs.example.com $U@mhs.example.com

The address user@mhs.example.com maps to a Novell MHS subscriber user associated with a specified default MHS workgroup. The address user%wg@mhs.example.com maps to a Novell MHS subscriber user associated with the wg workgroup.

Although this addressing format is sufficient to access all available Novell MHS workgroups, it is sometimes useful to associate additional domain names with other Novell MHS workgroups This can be done with rewrite rules of the general form:

wg $U%wg.example.com wg.example.com $U%WG@mhs.example.com$E$F wg.example.com $U%wg.example.com@mhs.example.com$Cmhs_local wg.example.com $U%WG@mhs.example.com

These rules associate the domain name wg.example.com with the Novell MHS workgroup WG. Although these rules can look complex, their actions are reasonably straightforward: they insure that the Novell MHS name for the workgroup <(literal>(<)code>WG) is used in the headers of messages queued to the Novell MHS channel, while the domain name for the workgroup (wg.example.com) is used in all other cases. Any number of similar rule sets can be used to associate additional domain names with more remote Novell MHS workgroups.

Specification of extended MHS addresses is also possible. Use an address containing an attribute-value pair list (AVPL) of the general form (note the use of the forward slash, /):

/U=user/W=workgroup/T=extension-type/E=extension-value/@mhs-domain-name

This will map to the MHS address:

user@workgroup {extension-type:extension-value}

There are special quoting rules which must be observed when using AVPL style addresses. See Section 28.6.2.2 for details on using AVPL style addresses.

38.8.3.2.1 An Example Channel Configuration

mhs $U%mhs.example.com mhs.example.com $U@mhs.example.com

The contents of the corresponding lan.chans file might then appear as:

mhs_local master defragment charset8 ibm437 mhs.example.com

In the above example, when a local user addresses a message to xyz@mhs,or xyz@mhs.example.com, then the rewrite rules convert the address to xyz@mhs.example.com.

The resultant xyz@mhs.example.com is a fully qualified address but it doesn't refer to a real machine. It defines a pseudonym used to route messages to a specific channel. This pseudonym must appear in one and only one channel block.

If you have multiple MHS gateways, you might allow users to direct their messages to specific gateways. For example, you could use two pseudonyms based on NWENGR and NWSALES. The lan.rules file included into the main PMDF configuration file, pmdf.cnf would then appear as follows.

mhs $U%mhs.example.com mhs.example.com $U@mhs.example.com nwengr $U@nwengr.example.com nwsales $U@nwsales.example.com

The contents of the corresponding lan.chans file might then appear as follows. (Note that additional option files are required for the added channels.)

mhs_local master defragment charset8 ibm437 mhs.example.com mhs_gw1 master defragment charset8 ibm437 nwengr.example.com mhs_gw2 master defragment charset8 ibm437 nwsales.example.com

When going to a single NetWare host, the MHS gateway channel is normally mhs_local. This channel name can vary. PMDF requires that it begin with mhs_.

38.8.3.3 Novell MHS Channel Option Files

The names of the mandatory options are

• MHS_IN,
• MHS_IPARCEL,
• MHS_OUT,
• MHS_OPARCEL,
• MHS_DEFAULT_WORKGROUP,
• MHS_GATEWAY_USERNAME,
• MHS_GATEWAY_WORKGROUP,
• MHS_GATEWAY_TYPE and
• MHS_ID_SUFFIX,

38.8.3.4 Location of the Option File

38.8.3.5 Format of the Option File

38.8.3.6 Contents of the Option File

ACCESS_METHOD (0)

Specifies the access method that PMDF will use to read and write message files. A value of 0, which is the default, selects normal I/O.

BINARY_ENCODING (string)

The BINARY_ENCODING option is optional. This option controls the MIME transfer encoding used when binary MHS attachments are converted into MIME bodyparts. Possible values include BASE32, BASE64, COMPRESSED-BASE64, BASE85, BINHEX, BTOA, HEXADECIMAL, PATHWORKS, QUOTED-PRINTABLE, X-UUENCODE, and COMPRESSED-UUENCODE. The MIME standard encoding BASE64 is the default and is appropriate in most cases. When such a message is read from a non-MIME aware user agent such as VMS MAIL, you can extract the MIME bodyparts between the MIME boundary markers to a file and use the PMDF DECODE (OpenVMS) or pmdf decode (UNIX) utility to decode it. From a MIME aware user agent such as PMDF MAIL or Pine, just use the appropriate command to extract a message part and it will be automatically decoded (e.g., PMDF MAIL's EXTRACT/PART command). A different encoding can be appropriate when messages always go to another mail system which does not support MIME or the MIME encodings.

MHS_DEFAULT_WORKGROUP (string)

When an address inbound to MHS does not contain an explicit workgroup or host name, PMDF uses this value since SMF requires a Workgroup Name component in each address. See the discussion under Section 38.8.4. For a site with a single NetWare file server, this will be the host name of that file server. For multi-host workgroups, the value of this option should match the response to the Workgroup name prompt in the Host Setup screen. To review this field, run the MHS Directory Manager, select Manage Directories, and select Set up: This host.

MHS_GATEWAY_HOST (string)

This option is used to associate a RFC 822 style pseudodomain name with a MHS style gateway name. MHS users can then send mail to addresses of the form user@gateway and it will actually go out the PMDF gateway and be turned into an address of the form user@pseudodomain.

MHS_GATEWAY_TYPE (string)

Required option which specifies the type keyword that PMDF uses in outbound messages. It is required by the MHS Extended Address format. It has no intrinsic meaning. Normally, the value is SMTP or PMDF.

Note Novell MHS users address mail to PMDF users with an address of the form: pmdfusername@pmdfworkgroup {pmdftype:user@host} here user@host is any normal PMDF address; pmdfusername is the value of the MHS_GATEWAY_USERNAME option; pmdfworkgroup is the value of the MHS_GATEWAY_WORKGROUP option; and pmdftype is the value of the MHS_GATEWAY_TYPE option.

MHS_GATEWAY_USERNAME (string)

Required option which specifies a dummy username that PMDF uses in outbound messages as required by the MHS Extended Address format. It is only used when PMDF must use Extended Addresses. The dummy username has no intrinsic meaning. If PMDF can use Basic Address format, it will and this username isn't used at all in that address. Usually, the value of MHS_GATEWAY_USERNAME is MAILER or PMDF. It can also be a hyphen, -. The hyphen fulfills the requirement for a non-blank word and has the connotation of place-holder.

MHS_GATEWAY_WORKGROUP (string)

Required option which specifies the name of the PMDF gateway on the MHS side. The value must match the response to the "Host Name" prompt in the "A Gateway" screen. While logged in as the MHS administrator, run the MHS Directory Manager, select "Manage Directories", select "routes to workgroups, hosts, and gateways", and select "Define A Gateway". Usually, this name will be PMDF. To direct mail to the gateway, the PC user must use the value of this option as the workgroup name component following the user-workgroup delimiter, @, in the message's address.

MHS_ID_SUFFIX (string)

Each MHS message is assigned a sixteen character Unique ID (UID) string. When it needs a UID, PMDF generates an eight character value and appends whatever string you supply with this option. The resultant sixteen characters string is used as the UID. Choose an eight character string which is unique throughout your network. The first two characters must be "81" and the remaining six must be in the range 0-9, A-F. The Novell recommended procedure to create a UID is PC specific. It uses two characters of gateway type plus six characters from the NetWare file server's serial number. Since a system running PMDF probably doesn't have a direct connection to NetWare, PMDF can't depend on accessing the file server's serial number.

MHS_IN (string)

Novell MHS communicates with each gateway via a gateway-specific directory containing at least four subdirectories. On the NetWare MHS side, the IN subdirectory contains messages to be imported into Novell MHS, the IPARCEL subdirectory contains attachments for messages in the IN subdirectory, the OUT subdirectory contains messages exported from MHS to be picked up by the gateway, and the OPARCEL subdirectory contains attachments for messages in the OUT subdirectory. Files must be transferred from the channel's MHS_OUT and MHS_OPARCEL directories to MHS's IN and IPARCEL directories. Files must also be transferred from MHS's OUT and OPARCEL directories to the channel's channel's MHS_IN and MHS_IPARCEL directories. PMDF does not automatically provide this. The installer must set up this copy, or transfer, process. Some utilities are provided to assist with this task. The installer must also ensure that the Novell MHS Connectivity Manager is operating. This option specifies the device and directory path on the system running PMDF where messages which are inbound to PMDF are stored.

MHS_IPARCEL (string)

Location of any attachments associated with messages inbound to PMDF. Each attachment file is associated with exactly one header file in the MHS_IN directory. See the description under the MHS_IN option. This option specifies the device and directory path on the system running PMDF where attachment files are stored.

MHS_OPARCEL (string)

Location of any attachments associated with messages outbound from PMDF. Each attachment file is associated with exactly one header file in the MHS_OUT directory. See the description under the MHS_IN option. Specifies the device and directory path on the system running PMDF where the attachment files are stored.

MHS_OUT (string)

Location of messages outbound from PMDF. Each file contains the header information, including the names of any attachments, and the main body part. See the description under the MHS_IN option. Specifies the device and directory path on the system running PMDF where the messages which are outbound from PMDF are stored.

MHS_SLAVE_DELETE (0 or 1)

Specify MHS_SLAVE_DELETE=0 if you are testing and do not want Novell MHS message files to be deleted automatically by MHS_SLAVE. The default is 1. If this is set incorrectly, you will get duplicate messages.

REPEAT_COUNT (integer)

SLEEP_TIME (integer)

PMDF's MHS channel shares the files it produces with the Novell MHS Connectivity Manager. Moreover, the actual file server facilities used to provide the necessary file access are quite variable. Some file servers, in an effort to get improved performance, can employ various caching techniques. Use of these techniques can result in transient accessibility problems when the Novell MHS channel attempts to read its message files. The REPEAT_COUNT and SLEEP_TIME options are provided as a means to work around file server specific problems. The REPEAT_COUNT option specifies how many times the channel programs will attempt to open an input file before giving up. REPEAT_COUNT defaults to 2 (two attempts). The SLEEP_TIME option is provided as a means to work around file server specific problems. The SLEEP_TIME option specifies how long in seconds the channel program waits between attempts. SLEEP_TIME defaults to 2 (two seconds between retries).

TIMEZONE (string)

For messages coming in from MHS to PMDF, specifies the default time zone to assume for incoming MHS time values that don't have a zone explicitly specified.

38.8.3.7 Example Option Files

The following is an example on OpenVMS system.

MHS_GATEWAY_WORKGROUP=PMDF MHS_GATEWAY_USERNAME=MAILER MHS_GATEWAY_TYPE=SMTP MHS_ID_SUFFIX=81BADD28 ! MHS_DEFAULT_WORKGROUP=EXAMPLE ! MHS_IN=d1:[pmdf_mhs.in] MHS_IPARCEL=d1:[pmdf_mhs.iparcel] MHS_OUT=d1:[pmdf_mhs.out] MHS_OPARCEL=d1:[pmdf_mhs.oparcel]

The following is an example on UNIX.

MHS_GATEWAY_WORKGROUP=PMDF MHS_GATEWAY_USERNAME=MAILER MHS_GATEWAY_TYPE=SMTP MHS_ID_SUFFIX=81BADD28 ! MHS_DEFAULT_WORKGROUP=EXAMPLE ! MHS_IN=/dev1/pmdf_mhs/in/ MHS_IPARCEL=/dev1/pmdf_mhs/iparcel/ MHS_OUT=/dev1/pmdf_mhs/out/ MHS_OPARCEL=/dev1/pmdf_mhs/oparcel/

38.8.4 Addressing MHS from PMDF

mhs_user%mhs_host@mhs_gw

From VMS MAIL, use:

IN%"mhs_user%mhs_host@mhs_gw"

If mhs_user is a username on the default MHS workgroup (see MHS_DEFAULT_WORKGROUP in Section 38.8.3.3), then both the percent sign and mhs_host component can be omitted giving mhs_user@mhs_gw. If present, the mhs_host is the name of a NetWare host or MHS workgroup. In either format, the mhs_gw portion works with the PMDF rewrite rules to actually route the message to a particular channel block and to a specific MHS gateway.

38.8.5 Addressing PMDF from MHS

username@workgroup_name {other_non-SMF_route}

username@workgroup_name forms a MHS Basic Address. Each part must be eight characters or less and use only the letters A--Z, a--z, the digits 0--9, and the symbols -, $, and #. This form can be used to send mail to a remote address, such as a VMS MAIL user (assuming their username is eight characters or less). Since percent signs are not allowed, there is no standard way of specifying a host name on the PMDF side of the gateway, so it will be delivered to username on the PMDF system.

If the user agent on the PC allows a percent sign in username, you can use final_user%final_host@workgroup_name, where final_user is the username and final_host is the host name of the destination system. A severe constraint, however, is that the total length of final_user%final_host must be eight characters or less.

The braces, and text contained within, are optional. If present, they signify an MHS Extended Address. The extended address form must be used when username exceeds the MHS eight character limit or when the user is not located on that system running the PMDF gateway software.