MAILbus 400 SMTP Gateway for_DIGITAL_UNIX______________________________ Release Notes Revision/Update Information: Version 2.1B Digital Equipment Corporation Maynard, Massachusetts __________________________________________________________ Digital Equipment Corporation makes no representations that the use of its products in the manner described in this publication will not infringe on existing or future patent rights, nor do the descriptions contained in this publication imply the granting of licenses to make, use, or sell equipment or software in accordance with the description. Possession, use, or copying of the software described in this publication is authorized only pursuant to a valid written license from DIGITAL or an authorized sublicensor. No responsibility is assumed for the use or reliability of software on equipment that is not supplied by Digital Equipment Corporation or its affiliated companies. © Digital Equipment Corporation 1995,1998. All Rights Reserved. The following are trademarks of Digital Equipment Corporation: DECnet, DIGITAL, MAILbus, VAX DOCUMENT, and the DIGITAL logo. Internet is a registered trademark of Internet, Inc. Microsoft Exchange is a trademark of Microsoft Corporation. OSI is a registered trademark of CA Management, Inc. UNIX is a registered trademark in the United States and other countries, licensed exclusively by X/Open Company, Ltd. This document was prepared using VAX DOCUMENT, Version 2.1. ________________________________________________________________ Contents Part I Introduction 1 Introduction.................................... 3 Part II Installing Version 2.1B and Changes Introduced in Version 2.1B 2 Installing Version 2.1B......................... 7 3 Differences Between Version 2.1B and V2.1A...... 8 3.1 Year 2000 Compliance ......................... 9 3.2 Improved Handling of X.400 Trace Headers ..... 9 3.3 Tested also on Digital UNIX V4.0D ............ 9 3.4 Readers Comments ............................. 9 Part III Restrictions and Documentation Errors 4 Restrictions in This Version of the SMTP Gateway......................................... 13 4.1 Quotation Marks Must Be Omitted in Address Test Tool Input............................... 13 4.2 Syntactical Errors in O/R Addresses .......... 13 4.3 Bug in Example custom_decode Script .......... 14 5 Restrictions in Other Products That Can Affect the SMTP Gateway ............................... 14 5.1 Microsoft Exchange Address Encapsulation Problem in Some Releases...................... 14 5.2 Sendmail Truncates Addresses Longer Than 200 Characters.................................... 14 5.3 Sendmail Removes Blind Carbon Copy Headers from Messages................................. 15 5.4 Two Digit Years used by External Software .... 15 iii Part IV Background to Previous Kits 6 Changes Introduced in Version 2.1A.............. 19 6.1 General Functions ............................ 19 6.2 Changes Relating to the MIME X.400 Enhanced Relay (MIXER)................................. 19 6.3 Changes in Addressing Functions .............. 19 6.4 Changes Relating to Headers .................. 20 7 New Features for Version 2.1 ................... 20 7.1 Support for the Multipurpose Internet Mail Extensions Defined in RFC 1522................ 20 7.2 Support for Parts of MIXER ................... 21 7.3 New Summary Event - Gateway Status .......... 21 7.4 Support for Remote MTA ....................... 21 8 Changes Since Version 2.0....................... 21 8.1 Interworking with Other MIME Products ........ 21 8.2 New X-Author Header .......................... 22 8.3 More Precise sendmail Rules .................. 22 8.4 Changes in O/R Address Translation ........... 22 8.5 Running the Setup Procedure to Reinstate Rewrite Rules................................. 22 9 Changes Since Version 1.*....................... 23 9.1 Support for RFC 1327, RFC 1494 and RFC 1495 .. 23 9.2 Untranslated Internet Message Headers Now Added to the End of X.400 Messages............ 23 9.3 Changes to the Way the SMTP Gateway Uses the MAILbus 400 MTA .............................. 24 9.4 Use Setup Procedure Instead of Editing the Startup NCL Script............................ 24 9.5 Additional Characteristic Attributes for Modifying Message Exchange.................... 25 9.6 Changes to the add_map and remove_map Tools .. 25 9.7 Changes to the Settings of the Address Lookup Attributes.................................... 27 iv Part I ________________________________________________________________ Introduction This part provides a brief introduction to the product and describes the structure of these notes. 1 Introduction The MAILbus[TM] 400 SMTP Gateway enables users of X.400- based and SMTP-based messaging systems (such as the Internet[R]) to exchange messages. The MAILbus 400 SMTP Gateway translates X.400 messages into the format used within the Internet (as defined in RFC 822), and translates Internet messages into X.400 format. These release notes are provided with Version 2.1B of the MAILbus 400 SMTP Gateway for DIGITAL[TM] UNIX[R]. They describe: o Information about installing this kit (see Section 2). o Differences between Version 2.1A and this kit (see Section 3). o The restrictions in this version of the MAILbus 400 SMTP Gateway (see Section 4). o The restrictions in other products that can affect the MAILbus 400 SMTP Gateway (see Section 5). o Changes introduced in all previous kits (see Part IV). 3 Part II ________________________________________________________________ Installing Version 2.1B and Changes Introduced in Version 2.1B This part is divided into two main sections, as follows: o Section 2 describes how to install Version 2.1B of the SMTP Gateway. o Section 3 describes the differences between Version 2.1B and Version 2.1A of the SMTP Gateway. 2 Installing Version 2.1B To install this kit follow the instructions in MAILbus 400 MTA Installing on a DIGITAL UNIX System, with the following exceptions: o Make sure you install one of the following configura- tions of prerequisite software: - DIGITAL UNIX V3.2G DECnet[TM]/OSI[R] for DIGITAL UNIX V3.2B MAILbus 400 MTA for DIGITAL UNIX (Base and Mgt Subsets) V2.0A DIGITAL X.500 Directory Service for DIGITAL UNIX (Base Subset) V3.0 - DIGITAL UNIX V4.0B with patches: OSF410-400151 (44.00), OSF410-400196 (85.00), and OSF410-400239-1 (136.01) DECnet/OSI for DIGITAL UNIX, V4.0A or later with dnaevld patched to 12-MAR-97, or later MAILbus 400 MTA for DIGITAL UNIX (Base and Mgt Subsets) V2.0A, or later DIGITAL X.500 Directory Service for DIGITAL UNIX (Base Subset) V3.1, or later - DIGITAL UNIX V4.0D (no UNIX patches are needed) DECnet/OSI for DIGITAL UNIX, V4.0A or later with dnaevld patched to 12-MAR-97, or later MAILbus 400 MTA for DIGITAL UNIX (Base and Mgt Subsets) V2.0B, or later DIGITAL X.500 Directory Service for DIGITAL UNIX (Base Subset) V3.1, or later o The command to deinstall any SMTP Gateway subsets already installed on your system is: # setld -d SXABASEnnn SXANETMANnnn SXADOCnnn Replace nnn with the version number of the subsets installed on your system. o The approximate disk space required (in Kilobytes) for each of the MAILbus 400 SMTP Gateway subsets in /usr /opt and /var/opt, and the corresponding softlinks for the MAILbus 400 SMTP Gateway's files in /usr and /var are shown in the following table. 7 _______________________________________________________ Subset Title Subset name Space Required in ____________________________________________/usr______/var MAILbus 400 SMTP SXANETMAN218 100kB 50kB Management MAILbus 400 SMTP Gateway SXABASE218 1550kB 400kB MAILbus 400 SMTP SXADOC218 50kB 800kB Supplementary_Documents________________________________ o The installation instructions are: - Mount the disk as follows: # mount -r /dev/cdrom-device-name /mnt where cdrom-device-name is the name of your CDROM device special file, usually rz4c. - Load the subsets as follows: # setld -l /mnt/sxa218/kit o The command to run the verification procedure (VP) is: # setld -v SXABASE218 The version number of this kit when displayed using NCL management is V2.1.8. To identify this kit, type the following command: what /usr/sbin/smtpgw/smtpgw | grep MAILbus The following is the response from this command: MAILbus 400 SMTP Gateway (mailer/daemon) V2.1B ddd mmm nn hh:mm:ss GMT 1998 3 Differences Between Version 2.1B and V2.1A Note that these notes specify all substantive changes made since the release of Version 2.1A of the SMTP Gateway. This release is numbered Version 2.1B but its kit number is 218; for example, the subset name is SXABASE218. Version 2.1B supersedes Version 2.1A released in 1997. 8 3.1 Year 2000 Compliance The MAILbus 400 SMTP Gateway also becomes Year 2000 Ready with its Version 2.1B release. Any two digit dates received by the Gateway are interpreted as follows: - Years "81" to "99" (inclusive) as "1981" to "1999" and - Years "00" to "80" (inclusive) as "2000" to "2080" MAILbus 400 SMTP Gateway is specified as Year 2000 Ready and will correctly process, calculate, compare and sequence date data from, into and between the twentieth and the twenty-first centuries and the years 1999 and 2000, including leap year calculations, when used in accordance with the associated DIGITAL Product documentation and provided that all hardware, firmware and software used in combination with such DIGITAL Products properly exchange date data with the DIGITAL Products. 3.2 Improved Handling of X.400 Trace Headers When passing through an X.400 Message Transfer System (MTS) consisting of several Message Transfer Agents (MTA's), several internal (internal to the MTS) trace headers are added to the message by each successive MTA. In one particular case, the Gateway would post an "Invalid X.400 Trace Header" error for a particular message arriving at the boundary. This problem has now been solved. 3.3 Tested also on Digital UNIX V4.0D The SMTP Gateway has been tested, successfully, for full functional capability on this new platform. No problems were encountered during the tests. 3.4 Readers Comments The address for Reader's comments as documented in the Release Notes and the books is no longer relevant. - Internet : migbooks@reo.mts.dec.com - X.400 : S=migbooks; O=digital; OU1=reo; P=digital; A=gold 400; C=gb Any comments on documentation should be directed to the local customer support centres. 9 If the readers have some comments to send they should use the prepaid readers' comments forms, if they are supplied at the back of the book. 10 Part III ________________________________________________________________ Restrictions and Documentation Errors This part lists the restrictions and documentation errors that apply to Version 2.1B and previous kits, as follows: o Section 4, Restrictions in This Version of the SMTP Gateway o Section 5, Restrictions in Other Products That Can Affect the SMTP Gateway 4 Restrictions in This Version of the SMTP Gateway This section describes restrictions in Version 2.1B of the SMTP Gateway. 4.1 Quotation Marks Must Be Omitted in Address Test Tool Input When entering an Internet address in the address test tool, you must not enclose encoded X.400 attributes in quotation marks. For example, when sending a message to the gateway you might use an address of the form To: "/OU=Finance/OU=Napier/PRMD=VEG/ADMD=NZ-PTT/C=NZ"@node8.x400 When entering the same address to the address test tool, however, you must omit the quotation marks: > /OU=Finance/OU=Napier/PRMD=VEG/ADMD=NZ-PTT/C=NZ@node8.x400 4.2 Syntactical Errors in O/R Addresses The SMTP Gateway always raises a Directory Configuration Error when a syntactically incorrect O/R address is constructed from a Foreign Address directory entry and data provided by the originator of an Internet message. The Problem Attribute in the Directory Configuration Error event is the full address received from Internet that would result in a syntactically incorrect O/R address. The gateway manager must examine this value and the corresponding Foreign Address entries in the directory to determine the origin of the error. A syntactical error might be either in one of these directory entries, or in the address supplied by the originator. The Constraint Error field indicates what sort of syntax error has occurred. This field has these possible values: o Too Many Characters Supplied An O/R term was too long, or contains non-printable characters. o Not Enough Characters Supplied An O/R name contains some Teletex attributes that would make up a Personal Name, but no Teletex Surname. o No Error 13 There is no error in the Foreign Address entry, but a constructed address would contain an incomplete set of Organisation Units, for example, /OU1 and /OU3 but no /OU2. 4.3 Bug in Example custom_decode Script The default custom_decode script shipped with Version 2.1B can fail on certain uuencoded bodyparts. Lines not labelled as compressed are inappropriately read and processed by an insufficiently precise grep command. 5 Restrictions in Other Products That Can Affect the SMTP Gateway This section lists restrictions in other products that can affect SMTP Gateway operation. 5.1 Microsoft Exchange Address Encapsulation Problem in Some Releases In some releases of Microsoft Exchange, the Internet Mail Connector does not correctly encapsulate RFC 822 addresses for inclusion in X.400 Domain-Defined Attributes. 5.2 Sendmail Truncates Addresses Longer Than 200 Characters It is possible for Internet addresses longer than approximately 200 characters to be truncated by some sendmail implementations. If a recipient's address is truncated by sendmail, the message cannot be delivered to the recipient, and a non-delivery report is returned to the originator. Internet addresses themselves do not tend to exceed the 200 character limit. However, if your Internet users need to include long O/R addresses in Internet addresses in order to address X.400 users, this problem could occur. Therefore, if your O/R addresses tend to be very long, you should consider setting up partial address translations for these O/R addresses. Then, Internet users no longer need to include the long O/R addresses in Internet addresses. Part II of MAILbus 400 SMTP Gateway Managing describes in detail how to set up address translations. 14 5.3 Sendmail Removes Blind Carbon Copy Headers from Messages When translating between Internet and X.400 messages, one of the message headers that the SMTP Gateway translates is the Blind Carbon Copy (BCC) header. However, some sendmail implementations remove BCC headers from all Internet messages they process. When the SMTP Gateway exchanges messages with such a sendmail implementation, no BCC headers will be present on the messages exchanged between Internet and X.400 users. This is because sendmail removes the BCC headers on Internet messages before they reach the SMTP Gateway and also removes the BCC headers on the Internet messages that the SMTP Gateway generates from X.400 messages. 5.4 Two Digit Years used by External Software The Gateway internally deals with years in 4 digits. However, when presented with 2-digit years, the Gateway interprets the years as follows : If YY is between 81 and 99 (inclusive), then CC is 19. (i.e., YYYY is 1981 - 1999). If YY is between 00 and 80 (inclusive), then CC is 20. (i.e.,YYYY is 2000 - 2080). 15 Part IV ________________________________________________________________ Background to Previous Kits This part gives a brief description of previous Versions of the SMTP Gateway. This information was available in the Release Notes for the previous kits and so might be familiar to you. It includes: o Section 6, Changes Introduced in Version 2.1A o Section 7, New Features for Version 2.1 o Section 8, Changes Since Version 2.0 o Section 9, Changes Since Version 1.* 6 Changes Introduced in Version 2.1A 6.1 General Functions o Delivery Status Notification(DSN)Correctly Formed o Thread-Safe System Libraries introduced o Repaired Transfer of Repertoire 1 Characters when Character Set Parameter is ISO-8859-1 o Changed Limit for Number of Connections to Server Process o GAteway Configurable to Receive 8-Bit Data bus Select Either 7-Bit or 8-Bit for Data Sent o IVP for NETMAN now running properly o More Accomodating MIME Boundaries 6.2 Changes Relating to the MIME X.400 Enhanced Relay (MIXER) o MIXER Conformance Enhanced o RFC 1327/MIXER Field Name Changes o Ordering of RFC 822 Headers now unchanged o Correction to Header Seperators 6.3 Changes in Addressing Functions o Removed Erroneous Parsing of Leading Hyphens o Improved Handling of Invalid sendmail Originator Field o No Segmentation Fault when PRMD term omitted from the Gateway's O/R Address o Successful Transfer of MIME Mail with many recipients o Successful Address Translation when O/R Address uses both Printable String and Teletex 19 6.4 Changes Relating to Headers o Corrected Parsing of Long Content-Type Field o "X-Disclose-Recipients:allowed" Setting now honoured o Corrected Mapping of Illegal Date Terms 7 New Features for Version 2.1 The following sections describe the new features that have been introduced in Version 2.1 of the SMTP Gateway. If upgrading, you must read the relevant chapter of MAILbus 400 SMTP Gateway Managing. 7.1 Support for the Multipurpose Internet Mail Extensions Defined in RFC 1522 The SMTP Gateway conforms to the Multipurpose Internet Mail Extensions (MIME) defined in RFC 1522. MIME is a standardized way of encoding headers and bodyparts that have always been difficult to transfer in RFC 822-based Internet systems, such as headers that use non-ASCII characters. To manage the new RFC 1522 encodings, there is a new attribute of the SMTP-Gateway entity, Header Encoding. By default, however, the setting of the Header Encoding attribute makes the SMTP Gateway generate non-MIME headers. Further details of the Header Encoding attribute are in both MAILbus 400 SMTP Gateway Managing and the SMTP Gateway Module Online Help. More information about the SMTP Gateway's conformance to relevant RFCs is provided in Appendix E of MAILbus 400 SMTP Gateway Managing. RFC 1522 is provided with the SMTP Gateway and is located at /var/smtpgw/doc/rfc1522.txt. 20 7.2 Support for Parts of MIXER MIXER is an Internet draft that defines the MIME X.400 Enhanced Relay. MIXER was, when Version 2.1 of the SMTP Gateway was released, still evolving. Version 2.1 of the SMTP Gateway implements the parts of MIXER that were comparatively stable. MAILbus 400 SMTP Gateway Managing gives details of which parts of MIXER are implemented. For further changes related to MIXER, see section 3.2 of MAILbus 400 SMTP Gateway Release Notes Version 2.1A. 7.3 New Summary Event - Gateway Status There is now a summary event, Gateway Status, that gives the overall status of the SMTP Gateway and points to any error event that stops the SMTP Gateway from running normally. For further details of this event see MAILbus 400 SMTP Gateway Managing or the SMTP Gateway Module Online Help. 7.4 Support for Remote MTA This release can support an MTA running on a different node from the SMTP Gateway. See MAILbus 400 SMTP Gateway Managing for details. 8 Changes Since Version 2.0 This section lists some significant changes since Version 2.0 of the SMTP Gateway. For further details of all these changes, see MAILbus 400 SMTP Gateway Managing. 8.1 Interworking with Other MIME Products In Version 2.0 of the SMTP Gateway, the transfer of binary bodyparts between Microsoft Exchange[TM] and the SMTP Gateway caused problems. This was as a result of the different ways of identifying bodyparts used by Microsoft Exchange and the SMTP Gateway. 21 8.2 New X-Author Header When sending a message from X.400 to the Internet, if the originator address consisted only of a free form name, previous versions of the SMTP Gateway constructed an invalid From: field. When a free form name is the only indication of where a message came from, Version 2.1 of the SMTP Gateway no longer produces a From: field, but instead produces a new header, X-Author. 8.3 More Precise sendmail Rules In previous versions, the SMTP Gateway used imprecise sendmail rules. Version 2.1 has changed the rules in several major ways: o The rules now use only the SMTP Gateway's RFC 822 domain name. o The rules are easier to edit than in previous versions. See Appendix F of MAILbus 400 SMTP Gateway Managing for details of the new rewrite rules. 8.4 Changes in O/R Address Translation The method the SMTP Gateway uses for translating from X.400 O/R addresses to SMTP addresses, is different now from the method used in previous versions. Previous versions of the SMTP Gateway used an Internet address supplied in the RFC 822 DDA only if the remainder of the O/R address matched the SMTP Gateway's own address or was in the directory. Now, if an RFC 822 DDA supplies an Internet address, the SMTP Gateway uses that address irrespective of any other O/R address terms. This is in accordance with MIXER. 8.5 Running the Setup Procedure to Reinstate Rewrite Rules This version of the SMTP Gateway adds rewrite rules to sendmail.cf when the setup procedure runs. Previous versions added rewrite rules when the SMTP Gateway was installed, and used a script to reinstate them. This script is no longer a part of the SMTP Gateway kit; to reinstate rewrite rules you simply run the setup script. 22 9 Changes Since Version 1.* Changes noted in this section are additional to the ones noted in Section 8, and apply only if you are upgrading from a Version 1.* SMTP Gateway. If you are upgrading from a Version 2.0 SMTP Gateway you can omit this section. 9.1 Support for RFC 1327, RFC 1494 and RFC 1495 Since Version 2.0, the SMTP Gateway has conformed to RFC 1327, which defines how gateways should translate the headers on Internet messages and messages based on the 1988 X.400 recommendations. RFC 1327 also defines how to translate between the bodies of Internet and X.400 messages, though these definitions have been superseded by RFC 1494 and RFC 1495. Version 2.1 of the SMTP Gateway continues to conform to both RFC 1494 and 1495 as described in Appendix E of MAILbus 400 SMTP Gateway Managing. RFC 1327, 1494 and 1495 are provided with the SMTP Gateway and are located at: /var/smtpgw/doc/rfc1327.txt /var/smtpgw/doc/rfc1494.txt /var/smtpgw/doc/rfc1495.txt 9.2 Untranslated Internet Message Headers Now Added to the End of X.400 Messages When the SMTP Gateway generates an X.400 message from an Internet message, it writes those Internet message headers that it could not translate into a text bodypart and places the bodypart at the end of the X.400 message. In Version 1.*, the SMTP Gateway added the untranslated Internet message headers in a bodypart at the beginning of the X.400 message. Note that the SMTP Gateway translates more Internet headers into X.400 headers than Version 1.*. This reduces the likelihood of a bodypart with untranslated Internet message headers being added to the end of the X.400 message. 23 9.3 Changes to the Way the SMTP Gateway Uses the MAILbus 400 MTA Since Version 2.0, the SMTP Gateway has not used the Shared File 1984 interface when connecting to the MAILbus 400 MTA; it uses the XAPI interface instead. Also, the SMTP Gateway no longer accesses the DIGITAL X.500 Directory Service directly; instead, it uses services provided by the MAILbus 400 MTA. As a result of these changes, two password attributes were added to the SMTP-Gateway entity: PW-Agent and PW-Domain. The PW-Agent attribute contains the password that provides the required authorization when the SMTP Gateway connects to the MTA. The PW-Domain attribute contains the password that provides the required authorization for the SMTP Gateway when it passes a request for directory information to the MTA. How to upgrade from a previous version of the SMTP Gateway is described in detail in MAILbus 400 SMTP Gateway Managing. 9.4 Use Setup Procedure Instead of Editing the Startup NCL Script The SMTP Gateway accesses and modifies information in the SMTP Gateway's startup NCL script each time you run the setup procedure. If you modify the SMTP Gateway's startup NCL script manually it is possible that the setup procedure subsequently fails to access or modify the information in the startup NCL script. Therefore we recommend that you always make changes to the SMTP Gateway's startup NCL script by running the setup procedure. 24 9.5 Additional Characteristic Attributes for Modifying Message Exchange A number of new characteristic attributes have been provided since Version 2.0 of the SMTP Gateway. With the exception of the Trace Logging attribute, these new attributes allow you to specify how the SMTP Gateway translates between X.400 and Internet messages. The new attributes are: Text Encoder Binary Encoder Character Set Character Translation Address Comments Trace Logging The SMTP Gateway is installed with values for these at- tributes that should be appropriate for most requirements. If you need to modify the settings of these attributes, run the SMTP setup procedure in the advanced mode. The new attributes and the setup procedure in the advanced mode are described in detail in Chapter 10 of MAILbus 400 SMTP Gateway Managing. 9.6 Changes to the add_map and remove_map Tools Changes have been made to the usage of the add_map and remove_map tools. You no longer need to use the -bothways parameter with the add_map tool in order to set up two address entries (that is, an O/R address entry and a foreign address entry) for the same user or group of users. In Version 2.0 of the SMTP Gateway, the following new parameters were introduced: o The -oneway parameter. Use this parameter to add different address entries to the directory, depending on whether an address translation is to be used in an originator or a recipient address. 25 o The -x400user parameter. Use this parameter to add address entries to the directory for X.400 users. With this parameter only the Internet translation is added to a user's O/R address entry; no content information and routing instruction is added. o The -i parameter. This parameter replaces the -r parameter. Use the -i parameter to indicate an Internet address in an add_map or remove_map command. For example, the following command sets up two address entries for the same user, that is, an O/R address entry and a foreign address entry: % /var/smtpgw/scripts/add_map -o "c=nz;a=nz-ptt;p=veg;ou1=gisborne;ou2=domestic;s=nimble" -i nimble@domestic.veggies.com Always enter add_map and remove_map commands on one line; the commands in this section are printed on several lines for clarity. In the following example one address entry is set up, indicated by the -oneway parameter: % /var/smtpgw/scripts/add_map -o "c=nz;a=nz-ptt;p=veg;ou1=gisborne;ou2=export;s=jameson" -i jameson@export.veggies.com -oneway Note also that the manpages for the add_map and remove_ map tools are no longer available. Instead, you can obtain online help on the add_map and remove_map tools by typing: % /var/smtpgw/scripts/add_map (for help on the add_map tool) % /var/smtpgw/scripts/remove_map (for help on the remove_map tool) More information on the add_map and remove_map tools is provided in Chapter 7 of MAILbus 400 SMTP Gateway Managing. 26 9.7 Changes to the Settings of the Address Lookup Attributes The SMTP Gateway has the following attributes, which specify how the SMTP Gateway is to translate addresses on messages: Lookup Internet Users Lookup X400 Users In Version 1.* of the SMTP Gateway these attributes had three settings: Off, Optional and Mandatory. Since Version 2.0, the SMTP Gateway has had only two settings for these attributes: Optional and Mandatory. The functionality of the Off setting has been included in the Optional setting. Therefore, if you have used the Off setting before, accept the value Optional when setting up the SMTP Gateway during the upgrade to Version 2.1. 27