Appendix B sendmail Migration and Compatibility

Netscape Messaging Server includes a sendmail emulator program to maintain compatibility with mail programs that employ Unix sendmail to deliver their mail. This appendix explains how to move user mail accounts and mail messages from a Unix sendmail system to Messaging Server. It also describes the similarities and differences between the Unix sendmail application and the Messaging Server sendmail emulator.

• Moving Users to Messaging Server
• Moving sendmail Messages to Messaging Server


• Compatibility with Unix sendmail

1. Use the unix2ldif utility to convert Unix user account information into an LDIF format file, for example, a file named file.ldif. For a detailed description of this step, see Running the unix2ldif Utility.
2. If the LDAP Directory already contains data, run the ldifsplit utility to split the LDIF file into two different LDIF format files:

• A file that contains new entries for users that are not already in the LDAP Directory.
• A file that contains the entries for those users who are already in the LDAP Directory.

For a detailed description of this step, see Running the ldifsplit Utility.

3. Use the chkuniq utility to check for duplicate DNs, user IDs, and email addresses. For a detailed description of this step, see Running the chkuniq Utility.
4. Update the LDAP Directory with the user information that is now in the LDIF format files. For a detailed description of this step, see Updating the LDAP Directory.
5. Use the chkuniq utility to perform a final check for duplicate DNs, user IDs, and email addresses on the LDAP Directory.
6. Use the MigrateUnixSpool utility to move messages from users' sendmail spool files to the Messaging Server mailbox directories. See Moving sendmail Messages to Messaging Server.

The unix2ldif utility writes your sendmail user account information to an LDIF (LDAP Data Interchange Format) file. The unix2ldif utility creates one LDAP entry in the LDIF file for each user account. If an account is skipped, the utility gives you a warning. The LDIF file contains the following information:

• User accounts
• Mail groups


• Forwarding aliases

• /etc/passwd
• /etc/shadow (/etc/security/shadow on IBM AIX systems.)


• /etc/aliases /etc/passwd file.

unix2ldif -b dn -d domain [options] > file.ldif

A routing alias for a user can be in the format user: user@hostname or the format user@hostname.HostCompletionDomain. For example, esperanza: esperanza@sirius or esperanza@sirius.airius.com. The user ID and the user portion of the routing alias must match exactly (case-sensitive match).

• If the -H option is used to specify a host name, that host name is used to set the mailHost value. When the -H option is used, the aliases file is not used to determine how to set mailHost. (For more information on aliases files, see unix2ldif and aliases Files.)
• If the -h option is used to specify a host name, that host name is used to set the mailHost value for users who do not have a routing alias in the aliases file. Users that do have a routing alias in the aliases file have that alias used as their mailHost value.
• If neither the -H nor the -h options are used to specify a host name, unix2ldif obtains the mailHost value from the aliases file.

This section describes how to use the -d and -D address and host completion domain options.

The -d option is used to set the address completion domain(s). Address completion domains are used to generate the email addresses of a given user.

unix2ldif -b dn -d airius.com -d other.com > file.ldif

mail:lincoln@airius.com
mailAlternateAddress: lincoln@other.com

mail:lincoln@airius.com
mailAlternateAddress: lincoln@other.com
mailAlternateAddress: abe@airius.com
mailAlternateAddress: abe@other.com
mailAlternateAddress: my_captain@airius.com
mailAlternateAddress: my_captain@other.com 

The -D option is used to set the host completion domain. If -D is not used, unix2ldif uses the primary address completion domain (the value specified with the -d) as the host completion domain.

• When determining whether an aliases file entry is a routing alias of the form user@host.HostCompletionDomain, unix2ldif uses the host completion domain as defined here in the comparison. (For more information on routing aliases, see Routing Aliases, and unix2ldif and aliases Files.)
• When formulating a user's mailHost value, if the information is a host name with no dot because the user's routing alias was user@hostname, or the -H or -h options were used with a host value with no dot, then unix2ldif appends a dot and the host completion domain to get the fully-qualified host name for the mailHost value. For example, if -h sirius is used and the HostCompletionDomain is airius.com, the mailHost value becomes sirius.airius.com.
• When creating a Forwarding Alias LDAP entry or a Mail Group LDAP entry, the forwarding target or group member is specified as user@hostname (where hostname is a host name with no dot). The HostCompletionDomain is then added to complete the entry in the format: user@hostname.HostCompletionDomain.

When unix2ldif reads an aliases file, each entry is assumed to be in one of two forms:

key: value
key value

A passwd file entry is considered by unix2ldif as a valid passwd file user account if all of the following are true:

• None of the following fields are empty: user ID, password, gecos (full name), and home directory.
• The encrypted password string is 13 characters. The unix2ldif utility first checks the password field in the passwd file, and if the field is not 13 characters long, it checks the shadow file where the password string must be 13 characters long.
• The user has a mail host. That is, the user has a routing alias in the aliases file, or the -h or -H options were specified.

The unix2ldif utility can also read Network Information Service (NIS) map files.

1. Use ypcat to copy the NIS map data to ASCII files as follows:

   ypcat passwd > /tmp/passwd.txt
   ypcat -k aliases > /tmp/aliases.txt

2. Run unix2ldif on the two /tmp/*.txt files you just created.

   unix2ldif -b dn -d domain -p /tmp/passwd.txt \
   -s /dev/null -a /tmp/aliases.txt > file.ldif

1. Use ypcat to copy the NIS map data to ASCII files as follows:

   ypcat passwd > /tmp/passwd.txt
   ypcat shadow > /tmp/shadow.txt
   ypcat -k aliases > /tmp/aliases.txt

2. Run unix2ldif on the three /tmp/*.txt files you just created.

   unix2ldif -b dn -d domain -p /tmp/passwd.txt \
   -s /tmp/shadow.txt -a /tmp/aliases.txt > file.ldif

The ldifsplit utility takes the LDIF file created by the unix2ldif utility (file.ldif) and splits it into two files:

• A file of LDAP entries that are already in the directory (the DN already exists). You can name this file whatever you want (this document uses the name mod.ldif because it will be used to modify the existing LDAP Directory entries).
• A file of LDAP entries that are not already in the directory (no DN exists). You can name this file whatever you want (this document uses the name add.ldif because it will be used to add new entries to the LDAP directory).

1. Export the contents of your LDAP server instance into an LDIF file. You can name the export file whatever you want (this document uses the name existing.ldif). See your Directory Server documentation for details on how to export a directory server instance.
2. Run the ldifsplit utility using the following syntax (assuming that the unix2ldif output file is named file.ldif and the LDAP Directory export file is named existing.ldif):

    ldifsplit -f file.ldif -e existing.ldif -a add.ldif -m mod.ldif

With this syntax, ldifsplit compares the unix2ldif output file (file.ldif) to the existing contents of the LDAP Directory as contained in the export file (existing.ldif). The utility then creates two new files:

• mod.ldif containing entries for users who are already in the LDAP Directory.
• add.ldif containing new entries that are not in the LDAP Directory
3. Check the add.ldif and mod.ldif files to see if they contain any entries.

   tail add.ldif
   tail mod.ldif

If a file is empty, you do not need to do anything with it.

If either the add.ldif file or the mod.ldif file contains data, that data needs to be written into the LDAP Directory as described in Updating the LDAP Directory.

The chkuniq utility checks the output files of the unix2ldif and ldifsplit utilities and the contents of the existing LDAP Directory for duplicate entries. It checks the specified files for

• Duplicate DNs
• Duplicate user IDs


• Duplicate email addresses

1. Use chkuniq to make sure that the add.ldif file (or file.ldif) is internally consistent with no duplicates.

    chkuniq add.ldif

2. Use chkuniq to make sure that the existing.ldif file is internally consistent with no duplicates. (The existing.ldif file is created by exporting the current contents of the LDAP Directory to a file named existing.ldif.)

    chkuniq existing.ldif

3. Use chkuniq to compare the add.ldif file and existing.ldif files against each other.

    chkuniq add.ldif existing.ldif

The final stage of moving users from a Unix sendmail system to Netscape Messaging Server is to update the LDAP Directory with the account information converted from sendmail.

• If you ran ldifsplit to create add.ldif and mod.ldif files, update the LDAP Directory from each of those two files.
• If you did not run ldifsplit, update the LDAP Directory from the file.ldif file created by unix2ldif.

• Database Manager. The Netscape Directory Server provides a Database Manager that can be used to update the LDAP Directory as described in Updating the LDAP Directory with Database Manager.
• ldapmodify. You can also use the ldapmodify command-line utility to update the LDAP Directory as described in Updating the LDAP Directory with ldapmodify.

You can use the Database Manager feature to write the user account information in the LDIF files to the LDAP Directory instance on the Directory Server.

1. Make sure the Directory Server is running.
2. Log in to the Directory Server. You must have read and execute permission to use Database Manager and read and write permissions for the targeted entries in the LDAP directory. (You can run this remotely using -h host.)
3. Go to the Database Manager screen as described in your Directory Server documentation.
4. Select the Add Entries form.
5. In the Full Path to LDIF File field, enter the full path name to the LDIF file that contains the entries you want to add.

If you created add.ldif and mod.ldif files by running ldifsplit, enter the full path and name of the add.ldif file. For example, if you ran ldifsplit in the /tmp directory: /tmp/add.ldif. Then repeat the process for mod.ldif.

If you did not run ldifsplit, enter the full path and name of the unix2ldif output file. For example: /tmp/file.ldif.

6. Leave the Bind to Server field as is.
7. The Password field should already contain the correct password.
8. Choose Okay. The entries are added to your Directory Server manager.

You can use the ldapmodify command-line utility to write the sendmail user account information in the LDIF files to the LDAP Directory instance on the Directory Server.

1. Make sure the Directory Server is running.
2. Log in to the Directory Server system as root.
3. Go to the directory containing the LDIF files.
4. Run ldapmodify to update the LDAP Directory:

If you created add.ldif and mod.ldif files by running ldifsplit, run ldapmodify on both files:

   ldapmodify -D "cn=Directory Manager" -w password -f mod.ldif
   ldapmodify -D "cn=Directory Manager" -w password -a -f add.ldif

If you did not run ldifsplit, run ldapmodify on the unix2ldif output file. For example: file.ldif

   ldapmodify "cn=Directory Manager" -w password -a -f file.ldif

The MigrateUnixSpool utility reads messages from the user's sendmail mailbox and appends them to the user's Messaging Server mailbox.

MigrateUnixSpool -u uid -o mailspool -d destmailhost 
  -a admin -v password -m destmaildrop

In this example, an administrator logged in as admin moves the spool file for someone with the user ID lincoln to the Messaging Server host mailserver in the primary partition.

MigrateUnixSpool -u lincoln -o /var/mail/lincoln -d mailserver 
   -a admin -v password -m server-root/msg-instance/store/partition/
   primary

The Messaging Server includes a program named sendmail that emulates the Unix sendmail program in the /usr/lib directory. Most of Unix sendmail's functionality is performed by one or more modules in the Messaging Server, so the sendmail emulator is primarily for compatibility with many mail programs that employ Unix sendmail (rather than SMTP) to deliver their mail. The Messaging Server sendmail emulator program can also be used to start up the Messaging Server mail system and to check and deliver the mail queue.

The Messaging Server sendmail emulator maintains compatibility with existing software that delivers mail using the Unix sendmail command.

/usr/lib/sendmail -t < /tmp/message
cat file1 | /usr/lib/sendmail -oem recip1,recip2

Because Unix sendmail comes installed on most Unix-based machines, many scripts, such as system boot scripts, exist to start up sendmail. This is done with a command such as:

/usr/lib/sendmail -bd -q30m

Some system administrators are used to typing mailq to check for queued messages. The sendmail emulator provided with the Messaging Server will respond to this command with the contents of the mail queue. However, many server administrators now prefer to use the Messaging Server mail queue form, which makes processing the queue easier.

The Unix sendmail program has several other operating modes that aren't necessary or are not supported by the Messaging Server. For a complete list of supported operating modes and command-line options and options, see Functional Compatibility.

The following sections specify the differences between Unix sendmail and the Messaging Server sendmail emulator with regard to SMTP, aliases and mail forwarding, program delivery, file delivery, and mailing lists.

The Messaging Server is preconfigured for interacting with other machines on the Internet.

Unix sendmail supports several types of aliases in the /etc/aliases file and in users' personal .forward files. The various types of aliases allow:

• Local users to receive mail at several addresses
• Messages to be distributed to multiple recipients


• Messages to be forwarded to users at other machines

Using Unix sendmail, you can create an alias or forward that delivers incoming mail to a program. The program then reads the mail and performs some operation depending on the mail contents. These types of programs usually filter messages into different mailboxes or send out automatic replies such as vacation notices. This functionality makes it easy to extend the mail system, but is problematic with respect to security.

Unix sendmail makes it possible to set up an alias or .forward file to append mail to a file. This can be used to keep a record of incoming mail or to delete incoming mail by sending it to /dev/null. However, for delivery-to-file needs the author of sendmail recommends using an alternate delivery agent invoked through the delivery-to-program facility.

Mailing lists in Unix sendmail are implemented using aliases and program deliveries. List recipients are stored either in the aliases database or in an external file using an :include: alias. Several mailing-list administration programs are available that can automate the task of maintaining recipient distribution lists, while sendmail handles the delivery of the messages.

Table B.5 in this section lists the alias names you can use to run the Messaging Server sendmail emulator program. Table B.6 lists and describes the available command-line arguments that the sendmail emulator program recognizes. Certain options are recognized (through the -o command-line option), and their effects are described in Table B.7.

You can run the Unix sendmail program under several names as a shorthand way to specify the action to perform. The Messaging Server sendmail emulator program recognizes several of these alternate names. The behavior that results from invoking the sendmail emulator with an alternate name is summarized in Table B.5.

The Messaging Server sendmail emulator doesn't need a configuration file (sendmail.cf), yet most of Unix sendmail's options can be set from the command line. Many of the options are meant for the sendmail daemon, but some of them are relevant to the normal operation of sending mail.