Chapter 25 Mail Services (Tasks)

This chapter describes how to set up and administer mail services. If you are not familiar with administering mail services, read Chapter 24, Mail Services (Overview) for an introduction to the components of mail services and for a description of a typical mail service configuration (as shown in Figure 24–1). The following list can help you find groups of related procedures that are covered in this chapter.

• Mail Services Task Map

• Setting Up Mail Services (Task Map)

• Administering Mail Alias Files (Task Map)

• Administering the Queue Directories (Task Map)

• Administering .forward Files (Task Map)

• Troubleshooting Procedures and Tips for Mail Services (Task Map)

See Chapter 26, Mail Services (Reference) for a more detailed description of the components of mail services. This chapter also describes the mail service programs and files, the mail routing process, and the interactions of sendmail with name services.

See Chapter 27, What's New With Mail Services (Reference) for a description of the new features that are included in version 8.12 of sendmail, the version that is in this Solaris 9 release. You can also read about changes to mail.local, mailstats, and makemap. Chapter 27, What's New With Mail Services (Reference) also provides a description of a new maintenance command, editmap.

Mail Services Task Map

The following table refers you to task maps throughout this chapter that focus on a specific group of procedures.

Planning Your Mail System

The following list describes some concerns that should be part of your planning process.

• Determine the type of mail configuration that meets your requirements. This section describes two basic types of mail configuration and briefly lists what you need to set up each configuration. If you need to set up a new mail system or if you are expanding an existing one, you might find this section useful. Local Mail Only describes the first configuration type, and Local Mail and a Remote Connection describes the second type.

• As necessary, choose the systems that are to act as mail servers, mail hosts, and mail gateways.

• Make a list of all the mail clients for which you are providing service and include the location of their mailboxes. This list can help you when you are ready to create mail aliases for your users.

• Decide how you plan to update aliases and forward mail messages. You might set up an aliases mailbox as a place for users to send requests for mail forwarding and for changes to their default mail alias. If your system uses NIS or NIS+, you can administer mail forwarding, rather than requiring users to manage it themselves. Administering Mail Alias Files (Task Map) provides a list of tasks that are related to aliasing. Administering .forward Files (Task Map) provides a list of tasks that are related to managing .forward files.

After you have completed the planning process, you need to set up systems on your site to perform the functions that are described in Setting Up Mail Services (Task Map). For other task information, refer to Mail Services Task Map.

Local Mail Only

The simplest mail configuration, shown in Figure 25–1, is two or more workstations that are connected to one mail host. Mail is completely local. All the clients store mail on their local disks and act as mail servers. Mail addresses are parsed by using the /etc/mail/aliases files.

Figure 25–1 Local Mail Configuration

To set up this kind of mail configuration, you need the following.

• The default /etc/mail/sendmail.cf file on each mail client system (no editing is required).

• A server that is designated as the mail host. You can make this designation by adding mailhost.domain_name to the /etc/hosts file on the mail host. Then, if you are not running NIS or NIS+, add the mail host IP address line to the /etc/hosts file of all mail clients.

• Matching /etc/mail/aliases files on any system that has a local mailbox (unless you are running NIS or NIS+).

• Enough space in /var/mail on each mail client system to hold the mailboxes.

For task information on setting up your mail service, refer to Setting Up Mail Services (Tasks). If you are looking for a particular procedure that is related to setting up your mail service, refer to Setting Up Mail Services (Task Map).

Local Mail and a Remote Connection

The most common mail configuration in a small network is shown in Figure 25–2. One system includes the mail server, the mail host, and the mail gateway to the outside world. Mail is distributed by using the /etc/mail/aliases files on the mail gateway. No name service is required.

Figure 25–2 Local Mail Configuration With a UUCP Connection

In this configuration, you can assume that the mail clients mount their mail files from /var/mail on the mail host. To set up this kind of mail configuration, you need the following.

• The main.cf file on the mail gateway (no editing is required if Mail Exchanger [MX] records are used).

• The default /etc/mail/sendmail.cf file on each mail client system (no editing is required).

• A server that is designated as the mail host. You can make this designation by adding mailhost.domain_name to the /etc/hosts file on the mail host. Then, if you are not running NIS or NIS+, add the IP address line for the mail host to the /etc/hosts file of every mail client.

• Matching /etc/mail/aliases files on any system that has a local mailbox (unless you are running NIS or NIS+).

• Enough space in /var/mail on the mail server to hold the client mailboxes.

For task information on setting up your mail service, refer to Setting Up Mail Services (Tasks). If you are looking for a particular procedure that is related to setting up your mail service, refer to Setting Up Mail Services (Task Map).

Setting Up Mail Services (Task Map)

The following table describes the procedures for setting up mail services.

Setting Up Mail Services (Tasks)

You can readily set up a mail service if your site does not provide connections to email services outside your company or if your company is in a single domain.

Mail requires two types of configurations for local mail. Refer to Figure 25–1 in Local Mail Only for a representation of these configurations. Mail requires two more configurations for communication with networks outside your domain. Refer to Figure 24–1 in Overview of the Hardware Components or Figure 25–2 in Local Mail and a Remote Connection for a representation of these configurations. You can combine these configurations on the same system or provide them on separate systems. For example, if your mail host and mail server functions are on the same system, follow the directions in this section for setting up that system as a mail host. Then, follow the directions in this section for setting up the same system as a mail server.

The following procedures for setting up a mail server and mail client apply when mailboxes are NFS mounted. However, mailboxes typically are maintained in locally mounted /var/mail directories, which eliminates the need for the following procedures.

How to Set Up a Mail Server

No special steps are required to set up a mail server that is only serving mail for local users. The user must have an entry in the password file or in the name space, and the user should have a local home directory (for checking the ~/.forward file) for mail to be delivered. For this reason, home directory servers are often set up as the mail server. Hardware Components in Chapter 26, Mail Services (Reference) provides more information about the mail server.

The mail server can route mail for many mail clients. The only resource requirement for this type of mail server is that it have adequate spooling space for client mailboxes.

Either the /var/mail directory should be available for remote mounting or a service such as Post Office Protocol (POP) or Internet Message Access Protocol (IMAP) should be available from the server for clients to access their mailboxes. The following task shows you how to set up a mail server by using the /var/mail directory. To provide configuration guidelines for POP or IMAP is beyond the scope of this document.

For the following task, ensure that the /etc/dfs/dfstab file shows that the /var/mail directory is exported.

1. Become superuser on the mail server or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Stop sendmail.

   # /etc/init.d/sendmail stop

3. Check if the /var/mail directory is available for remote access.

   # share

   If the /var/mail directory is listed, proceed to step 5.

   If the /var/mail directory is not listed or if no list appears, continue with the appropriate substep.

   1. (Optional) If no list appears, start NFS services.

      Follow the procedure, How to Set Up Automatic File-System Sharing, to use the /var/mail directory to start NFS services.

   2. (Optional) If the /var/mail directory is not included in the list, add it to /etc/dfs/dfstab.

      Add the following command line to the /etc/dfs/dfstab file.

      share -F nfs -o rw /var/mail

4. Make the file system available for mounting.

   # shareall

5. Ensure that your name service has been started.

   1. (Optional) If you are running NIS, use this command.

      # ypwhich

      For more information, refer to the ypwhich(1) man page.

   2. (Optional) If you are running NIS+, use this command.

      # nisls

      For more information, refer to the nisls(1) man page.

   3. (Optional) If you are running DNS, use this command.

      # nslookup hostname

      hostname

      Use your host name.

      For more information, refer to the nslookup(1M) man page.

   4. (Optional) If you are running LDAP, use this command.

      # ldaplist

      For more information, refer to the ldaplist(1) man page.

6. Restart sendmail.

   # /etc/init.d/sendmail start

The mail.local program automatically creates mailboxes in the /var/mail directory the first time a message is delivered. You do not need to create individual mailboxes for your mail clients.

How to Set Up a Mail Client

A mail client is a user of mail services with a mailbox on a mail server and a mail alias in the /etc/mail/aliases file that points to the location of the mailbox. Hardware Components in Chapter 26, Mail Services (Reference) provides a brief description of a mail client.

You can also perform the task of setting up a mail client by using a service such as Post Office Protocol (POP) or Internet Message Access Protocol (IMAP). However, to provide configuration guidelines for POP or IMAP is beyond the scope of this document.

1. Become superuser on the mail client's system or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Stop sendmail.

   # /etc/init.d/sendmail stop

3. Ensure that a /var/mail mount point exists on the mail client's system.

   The mount point should have been created during the installation process. You can use ls to ensure that the file system exists. The following example shows the response you receive if the file system has not been created.

   # ls -l /var/mail /var/mail not found

4. Ensure that no files are in the /var/mail directory.

   If mail files do exist in this directory, you should move them so that they are not covered when the /var/mail directory is mounted from the server.

5. Mount the /var/mail directory from the mail server.

   You can mount the mail directory automatically or at boot time.

   1. (Optional) Mount /var/mail automatically.

      Add an entry such as the following to the /etc/auto_direct file.

      /var/mail -rw,hard,actimeo=0 server:/var/mail

      server

      Use the assigned server name.

   2. (Optional) Mount /var/mail at boot time.

      Add the following entry to the /etc/vfstab file. This entry permits the /var/mail directory on the mail server that is specified to mount the local /var/mail directory.

      server:/var/mail - /var/mail nfs - no rw,hard,actimeo=0

      The client's mailbox is automatically mounted any time the system is rebooted. If you are not rebooting the system, type the following command to mount the client mailbox.

      # mountall

      ---

      Caution –

      For mailbox locking and mailbox access to work properly, you must include the actimeo=0 option when mounting mail from an NFS server.

      ---

6. Update /etc/hosts.

   Edit the /etc/hosts file and add an entry for the mail server. This step is not required if you are using a name service.

   # cat /etc/hosts # # Internet host table # .. IP_address mailhost mailhost mailhost.example.com

   IP_address	Use the assigned IP addresses.
   example.com	Use the assigned domain.
   mailhost	Use the assigned mailhost.

   For more information, refer to the hosts(4) man page.

7. Add an entry for the client to one of the alias files.

   Refer to Administering Mail Alias Files (Task Map) for a task map about administering mail alias files.

   ---

   Note –

   The mail.local program automatically creates mailboxes in the /var/mail directory the first time a message is delivered. You do not need to create individual mailboxes for your mail clients.

   ---

8. Restart sendmail.

   # /etc/init.d/sendmail start

How to Set Up a Mail Host

A mail host resolves email addresses and reroutes mail within your domain. A good candidate for a mail host is a system that connects your network to the outside world or to a parent domain. The following procedure shows you how to set up a mail host.

1. Become superuser on the mail host system or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Stop sendmail.

   # /etc/init.d/sendmail stop

3. Verify the host-name configuration.

   Run the check-hostname script to verify that sendmail can identify the fully qualified host name for this server.

   % /usr/lib/mail/sh/check-hostname hostname phoenix OK: fully qualified as phoenix.example.com

   If this script is not successful in identifying the fully qualified host name, you need to add the fully qualified host name as the first alias for the host in /etc/hosts.

4. Update the /etc/hosts file.

   Choose the step that is appropriate for you.

   1. (Optional) If you are using NIS or NIS+, edit the /etc/hosts file on the system that is assigned to be the new mail host.

      Add the word mailhost and mailhost.domain after the IP address and system name of the mail host system.

      IP_address mailhost mailhost mailhost.domain loghost

      IP_address	Use the assigned IP address.
      mailhost	Use the system name of the mail host system.
      domain	Use the expanded domain name.

      The system is now designated as a mail host. The domain should be identical to the string that is given as the subdomain name in the output of the following command.

      % /usr/lib/sendmail -bt -d0 </dev/null Version 8.12.0+Sun Compiled with: LDAPMAP MAP_REGEX LOG MATCHGECOS MIME7TO8 MIME8TO7 NAMED_BIND NDBM NETINET NETINET6 NETUNIX NEWDB NIS NISPLUS QUEUE SCANF SMTP USERDB XDEBUG ============ SYSTEM IDENTITY (after readcf) ============ (short domain name) $w = phoenix (canonical domain name) $j = phoenix.example.com (subdomain name) $m = example.com (node name) $k = phoenix ========================================================

      See the following example of how the hosts file should look after these changes.

      # cat /etc/hosts # # Internet host table # 172.31.255.255 localhost 192.168.255.255 phoenix mailhost mailhost.example.com loghost

   2. (Optional) If you are not using NIS or NIS+, edit the /etc/hosts file on each system in the network and create the following entry.

      IP_address mailhost mailhost mailhost.domain loghost

5. Select the correct configuration file to copy and rename.

   The following command copies and renames the /etc/mail/main.cf file.

   # cp /etc/mail/main.cf /etc/mail/sendmail.cf

6. Restart sendmail.

   # /etc/init.d/sendmail start

7. Test your mail configuration.

   See How to Test the Mail Configuration for instructions.

For further information about mail hosts, refer to Hardware Components in Chapter 26, Mail Services (Reference).

How to Set Up a Mail Gateway

A mail gateway manages communication with networks outside your domain. The mailer on the sending mail gateway can match the mailer on the receiving system.

A good candidate for a mail gateway is a system that is attached to Ethernet and phone lines or a system that is configured as a router to the Internet. You can configure the mail host or another system as the mail gateway. You might choose to configure more than one mail gateway for your domain. If you have UNIX-to-UNIX Copy Program (UUCP) connections, you should configure the system (or systems) with UUCP connections as the mail gateway.

1. Become superuser on the mail gateway or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Stop sendmail.

   # /etc/init.d/sendmail stop

3. Select the correct configuration file to copy and rename.

   The following command copies and renames the main.cf file.

   # cp /etc/mail/main.cf /etc/mail/sendmail.cf

4. Verify the host-name configuration.

   Run the check-hostname script to verify that sendmail can identify the fully qualified host name for this server.

   # /usr/lib/mail/sh/check-hostname hostname phoenix OK: fully qualified as phoenix.example.com

   If this script is not successful in identifying the fully qualified host name, you need to add the fully qualified host name as the first alias for the host in /etc/hosts. If you need help with this step, refer to Step 4 of How to Set Up a Mail Host.

5. Ensure that your name service has been started.

   1. (Optional) If you are running NIS, use this command.

      # ypwhich

      For more information, refer to the ypwhich(1) man page.

   2. (Optional) If you are running NIS+, use this command.

      # nisls

      For more information, refer to the nisls(1) man page.

   3. (Optional) If you are running DNS, use this command.

      # nslookup hostname

      hostname

      Use your host name.

      For more information, refer to the nslookup(1M) man page.

   4. (Optional) If you are running LDAP, use this command.

      # ldaplist

      For more information, refer to the ldaplist(1) man page.

6. Restart sendmail.

   # /etc/init.d/sendmail start

7. Test your mail configuration

   See How to Test the Mail Configuration for instructions.

For more information about the mail gateway, refer to Hardware Components in Chapter 26, Mail Services (Reference).

How to Use DNS With sendmail

The DNS name service does not support aliases for individuals. This name service does support aliases for hosts or domains that use Mail Exchange (MX) records and cname records. You can specify host names, domain names, or both names in the DNS database. For more information about sendmail and DNS, see Interactions of sendmail With Name Services in Chapter 26, Mail Services (Reference), or see the System Administration Guide: Naming and Directory Services (DNS, NIS, and LDAP).

1. Become superuser or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Enable DNS host lookups (NIS+ only).

   Edit the /etc/nsswitch.conf file and remove the # from the hosts definition that includes the dns flag. The host entry must include the dns flag, as the following example shows, in order for the DNS host aliases to be used.

   # grep hosts /etc/nsswitch.conf #hosts: nisplus [NOTFOUND=return] files hosts: nisplus dns [NOTFOUND=return] files

3. Check for a mailhost and mailhost.domain entry.

   Use nslookup to ensure that an entry exists for mailhost and mailhost.domain in the DNS database. For more information, refer to the nslookup(1M) man page.

How to Set Up a Virtual Host

If you need to assign more than one IP address to a host, see this Web site: http://www.sendmail.org/virtual-hosting.html. This site provides complete instructions on how to use sendmail to set up a virtual host. However, in the “Sendmail Configuration” section, do not perform step 3b, as shown in the following.

# cd sendmail-VERSION/cf/cf
# ./Build mailserver.cf
# cp mailserver.cf /etc/mail/sendmail.cf

Instead, for the Solaris operating environment, perform the following steps.

# cd /usr/lib/mail/cf
# /usr/ccs/bin/make mailserver.cf
# cp mailserver.cf /etc/mail/sendmail.cf

Building the sendmail.cf Configuration File (Task) outlines these same three steps as part of the build process.

After you have generated your /etc/mail/sendmail.cf file, you can continue with the next steps to create a virtual user table, and so forth.

Building the sendmail.cf Configuration File (Task)

How to Build a New sendmail.cf File shows you how to build the configuration file. Although you can still use older versions of sendmail.cf files, the best practice is to use the new format.

For more details, you should read from the following resources.

• /usr/lib/mail/README provides a complete description of the configuration process.

• http://www.sendmail.org provides online information about sendmail configuration.

• Versions of the Configuration File and sendmail Configuration File, in Chapter 26, Mail Services (Reference), also provide some guidance.

The following sections in Chapter 27, What's New With Mail Services (Reference) identify new m4 configuration features.

• New and Revised Configuration File Options and Related Topics

• New and Revised m4 Configuration Macros for sendmail

How to Build a New sendmail.cf File

The following procedure shows you how to build a new configuration file.

/usr/lib/mail/cf/main-v7sun.mc is now /usr/lib/mail/cf/main.mc.

1. Become superuser or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Stop sendmail.

   # /etc/init.d/sendmail stop

3. Make a copy of the configuration files that you are changing.

   # cd /usr/lib/mail/cf # cp main.mc myhost.mc

   myhost

   Select a new name for your .mc file.

4. Edit the new configuration files (for example, myhost.mc), as necessary.

   For example, add the following command line to enable domain masquerading.

   # cat myhost.mc .. MASQUERADE_AS(`host.domain')

   host.domain

   Use the desired host name and domain name.

   In this example, MASQUERADE_AS causes mail that is sent to be labeled as originating from host.domain, rather than $j.

5. Build the configuration file by using m4.

   # /usr/ccs/bin/make myhost.cf

6. Test the new configuration file by using the -C option to specify the new file.

   # /usr/lib/sendmail -C myhost.cf -v testaddr </dev/null

   This command sends a message to testaddr while displaying messages as it runs. Only outgoing mail can be tested without restarting the sendmail service on the system. For systems that are not handling mail yet, use the full testing procedure in How to Test the Mail Configuration.

7. Install the new configuration file after making a copy of the original.

   # cp /etc/mail/sendmail.cf /etc/mail/sendmail.cf.save # cp myhost.cf /etc/mail/sendmail.cf

8. Restart the sendmail service.

   # /etc/init.d/sendmail start

Managing Mail Delivery by Using an Alternate Configuration (Task)

To facilitate the transport of inbound and outbound mail, the new default configuration of sendmail uses a daemon and a client queue runner. If you have disabled your daemon, you should perform the following task. For a detailed explanation, refer to New Configuration File, submit.cf.

How to Manage Mail Delivery by Using an Alternate Configuration of sendmail.cf

In the default configuration of sendmail, the client queue runner must be able to submit mail to the daemon on the local SMTP port. If the daemon is not listening on the SMTP port, the mail remains in the queue. To avoid this problem, perform the following task. For more information about the daemon and client queue runner and to understand why you might have to use this alternate configuration, refer to New Configuration File, submit.cf.

This procedure ensures that your daemon runs only to accept connections from the local host.

1. Become superuser or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Stop sendmail.

   # /etc/init.d/sendmail stop

3. Make a copy of the configuration file (either subsidiary.mc or main.mc, depending on your requirements) that you are changing. In this example, the subsidiary.mc file is used.

   # cd /usr/lib/mail/cf # cp subsidiary.mc myhost.mc

   myhost

   Select a new name for your .mc file.

4. Edit the new configuration file (for example, myhost.mc).

   Add the following lines before the MAILER() lines.

   # cat myhost.mc .. DAEMON_OPTIONS(`NAME=NoMTA4, Family=inet, Addr=127.0.0.1')dnl DAEMON_OPTIONS(`NAME=NoMTA6, Family=inet6, Addr=::1')dnl

5. Build the configuration file by using m4.

   # /usr/ccs/bin/make myhost.cf

6. Install the new configuration file after making a copy of the original.

   # cp /etc/mail/sendmail.cf /etc/mail/sendmail.cf.save # cp myhost.cf /etc/mail/sendmail.cf

7. Restart the sendmail service.

   # /etc/init.d/sendmail start

Administering Mail Alias Files (Task Map)

The following table describes the procedures for administering mail alias files. For more information on this topic, refer to Mail Alias Files in Chapter 26, Mail Services (Reference).

Administering Mail Alias Files (Tasks)

Mail aliases must be unique within the domain. This section provides the procedures for administering mail alias files. Alternately, you can use the AdminTool's Database Manager application to perform these tasks on the aliases database.

In addition, you can create database files for the local mail host by using makemap. Refer to the makemap(1M) man page. The use of these database files does not provide all of the advantages of using a name service such as NIS or NIS+. However, you should be able to retrieve the data from these local database files faster because no network lookups are involved. For more information, refer to Interactions of sendmail With Name Services and Mail Alias Files in Chapter 26, Mail Services (Reference).

How to Manage Alias Entries in an NIS+ mail_aliases Table

To manage entries in an NIS+ table, you can use the aliasadm command. To list, add, modify, or delete table entries with the aliasadm command, you begin a particular task with the following steps.

1. Either be a member of the NIS+ group that owns the table, or become root on the mail server, or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Complete your task by following the instructions from the example that meets your requirements.

   • Example—Initiating an NIS+ mail_aliases Table

   • Example—Listing the Entire Contents of the NIS+ mail_aliases Table

   • Example—Listing an Individual Entry From the NIS+ mail_aliases Table

   • Example—Listing Partial Matches From the NIS+ mail_aliases Table

   • Example—Adding Aliases to the NIS+ mail_aliases Table From the Command Line

   • Example—Adding Entries by Editing an NIS+ mail_aliases Table

   • Example—Editing Entries in an NIS+ mail_aliases Table

   • Example—Deleting Entries From an NIS+ mail_aliases Table

In some instances, you should begin the task by compiling a list of each of your mail clients, the locations of their mailboxes, and the names of the mail server systems.

Example—Initiating an NIS+ mail_aliases Table

To create a table, follow these instructions.

1. Either be a member of the NIS+ group that owns the table, or become root on the mail server, or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Initiate an NIS+ table.

   # aliasadm -I

3. Add entries to the table.

   • To add two or three aliases, refer to Example—Adding Aliases to the NIS+ mail_aliases Table From the Command Line.

   • To add more than two or three aliases, refer to Example—Adding Entries by Editing an NIS+ mail_aliases Table.

For more information, refer to the aliasadm(1M) man page.

Example—Listing the Entire Contents of the NIS+ mail_aliases Table

To see a complete list of the contents of the table, follow these instructions.

1. Either be a member of the NIS+ group that owns the table, or become root on the mail server, or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. List all of the entries in alphabetical order by alias.

   # aliasadm -1

For more information, refer to the aliasadm(1M) man page.

Example—Listing an Individual Entry From the NIS+ mail_aliases Table

To see an individual entry from the table, follow these instructions.

1. Either be a member of the NIS+ group that owns the table, or become root on the mail server, or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. List an individual entry.

   # aliasadm -m ignatz ignatz: ignatz@saturn # Alias for Iggy Ignatz

   The command matches only the complete alias name, not partial strings. You cannot use metacharacters (such as * and ?) with aliasadm -m.

For more information, refer to the aliasadm(1M) man page.

Example—Listing Partial Matches From the NIS+ mail_aliases Table

To see partial matches from the table, follow these instructions.

1. Either be a member of the NIS+ group that owns the table, or become root on the mail server, or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. List partial matches from the table.

   # aliasadm -l | grep partial_string

   partial_string

   Use the string of your choice for your search.

For more information, refer to the aliasadm(1M) man page.

Example—Adding Aliases to the NIS+ mail_aliases Table From the Command Line

To add two or three aliases to the table, follow these instructions.

1. Compile a list of each of your mail clients, the locations of their mailboxes, and the names of the mail server systems.

2. Either be a member of the NIS+ group that owns the table, or become root on the mail server, or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

3. (Optional) If necessary, initiate an NIS+ table.

   If you are creating a completely new NIS+ mail_aliases table, you must first initiate the table. To complete this task, refer to Example—Initiating an NIS+ mail_aliases Table.

4. Add aliases to the table.

   See this example of a typical entry.

   # aliasadm -a iggy iggy.ignatz@saturn "Iggy Ignatz"

   The following list describes the input from the preceding example.

   -a	The option for adding an alias
   iggy	The short form of the alias name
   iggy.ignatz@saturn	The expanded alias name
   "Iggy Ignatz"	The name for the alias in quotation marks

5. Display the entry you created and ensure that it is correct.

   # aliasadm -m alias

   alias

   The entry that you created

For more information, refer to the aliasadm(1M) man page.

Example—Adding Entries by Editing an NIS+ mail_aliases Table

To add more than two or three aliases to the table, follow these instructions.

1. Compile a list of each of your mail clients, the locations of their mailboxes, and the names of the mail server systems.

2. Either be a member of the NIS+ group that owns the table, or become root on the mail server, or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

3. Display and edit the aliases table.

   # aliasadm -e

   This command displays the table and enables you to edit it. The editor you use has been set with the $EDITOR environment variable. If this variable is not set, vi is the default editor.

4. Use the following format to type each alias on a separate line.

   alias: expanded_alias # ["option" # "comments"]

   alias	This column is for the short form of the alias name.
   expanded_alias	This column is for the expanded alias name.
   option	This column is reserved for future use.
   comments	This column is used for comments about the individual alias, such as a name for the alias.

   If you leave the option column blank, type an empty pair of quotation marks ("") and add the comments.

   The order of the entries is not important to the NIS+ mail_aliases table. The aliasadm -l command sorts the list and displays the entries in alphabetical order.

   For more information, refer to Mail Alias Files and the aliasadm(1M) man page.

Example—Editing Entries in an NIS+ mail_aliases Table

To edit entries in the table, follow these instructions.

1. Either be a member of the NIS+ group that owns the table, or become root on the mail server, or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Display the alias entry.

   # aliasadm -m alias

   alias

   Use the assigned alias name.

3. Edit the alias entry, as necessary.

   # aliasadm -c alias expanded_alias [options comments]

   alias	If necessary, edit the alias name.
   expanded_alias	If necessary, edit the expanded alias name.
   options	If necessary, edit the option.
   comments	If necessary, edit the comment for this entry.

   For more information, refer to the aliasadm(1M) man page, as well as Mail Alias Files.

4. Display the entry that you have edited and ensure that the entry is correct.

   # aliasadm -m alias

For more information, refer to the aliasadm(1M) man page.

Example—Deleting Entries From an NIS+ mail_aliases Table

To delete entries from the table, follow these instructions.

1. Either be a member of the NIS+ group that owns the table, or become root on the mail server, or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Delete an entry from the table.

   # aliasadm -d alias

   alias

   Use the alias name for the entry that you are deleting.

For more information, refer to the aliasadm(1M) man page.

How to Set Up an NIS mail.aliases Map

Use the following procedure to facilitate aliasing with an NIS mail.aliases map.

1. Compile a list of each of your mail clients, the locations of their mailboxes, and the names of the mail server systems.

2. Become root on the NIS master server or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

3. Edit the /etc/mail/aliases file, and make the following entries.

   1. Add an entry for each mail client.

      # cat /etc/mail/aliases .. alias:expanded_alias

      alias	Use the short alias name.
      expanded_alias	Use the expanded alias name (user@host.domain.com).

   2. Ensure that you have a Postmaster: root entry.

      # cat /etc/mail/aliases .. Postmaster: root

   3. Add an alias for root. Use the mail address of the person who is designated as the postmaster.

      # cat /etc/mail/aliases .. root: user@host.domain.com

      user@host.domain.com

      Use the assigned address of the designated postmaster.

4. Ensure that the NIS master server is running a name service to resolve the host names on each mail server.

5. Change to the /var/yp directory.

   # cd /var/yp

6. Apply the make command.

   # make

   The changes in the /etc/hosts and /etc/mail/aliases files are propagated to NIS slave systems and are active in only a few minutes, at most.

How to Set Up a Local Mail Alias File

Use the following procedure to resolve aliases with a local mail alias file.

1. Compile a list of each of your users and the locations of their mailboxes.

2. Become root on the mail server or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

3. Edit the /etc/mail/aliases file and make the following entries.

   1. Add an entry for each user.

      user1: user2@host.domain

      user1	Use the new alias name.
      user2@host.domain	Use the actual address for the new alias.

   2. Ensure that you have a Postmaster: root entry.

      # cat /etc/mail/aliases .. Postmaster: root

   3. Add an alias for root. Use the mail address of the person who is designated as the postmaster.

      # cat /etc/mail/aliases .. root: user@host.domain.com

      user@host.domain.com

      Use the assigned address of the designated postmaster.

4. Rebuild the alias database.

   # newaliases

   Depending on the configuration of the AliasFile option in /etc/mail/sendmail.cf, this command generates in binary form either the single file, /etc/mail/aliases.db, or the pair of files, /etc/mail/aliases.dir and /etc/mail/aliases.pag.

5. Perform one of the following steps to copy the file or files that were generated.

   1. (Optional) Copy the /etc/mail/aliases, the /etc/mail/aliases.dir, and the/etc/mail/aliases.pag files to each of the other systems.

      You can copy the three files by using the rcp or rdist commands. Refer to the rcp(1) man page or the rdist(1) man page for more information. Alternately, you can create a script for this purpose.

      When you copy these files, you do not need to run the newaliases command on each of the other systems. However, remember that you must update all the /etc/mail/aliases files each time you add or remove a mail client.

   2. (Optional) Copy the /etc/mail/aliases.db file to each of the other systems.

      You can copy the file by using the rcp or rdist commands. Refer to the rcp(1) man page or the rdist(1) man page for more information. Alternately, you can create a script for this purpose.

      When you copy this file, you do not need to run the newaliases command on each of the other systems. However, remember that you must update all the /etc/mail/aliases files each time you add or remove a mail client.

How to Create a Keyed Map File

To create a keyed map file, follow these instructions.

1. Become superuser on the mail server or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Create an input file.

   Entries can have the following syntax.

   old_name@newdomain.com new_name@newdomain.com old_name@olddomain.com error:nouser No such user here @olddomain.com %1@newdomain.com

   old_name@newdomain.com	Use the user name that was previously assigned with the domain that is newly assigned.
   new_name@newdomain.com	Use the address that is newly assigned.
   old_name@olddomain.com	Use the user name that was previously assigned with the domain that was previously assigned.
   olddomain.com	Use the domain that was previously assigned.
   newdomain.com	Use the domain that is newly assigned.

   The first entry redirects mail to a new alias. The next entry creates a message when an incorrect alias is used. The last entry redirects all incoming mail from olddomain to newdomain.

3. Create the database file.

   # /usr/sbin/makemap maptype newmap < newmap

   maptype	Select a database type, such as dbm, btree, or hash.
   newmap	Use the name of the input file and the first part of the name of the database file. If the dbm database type is selected, then the database files are created by using a .pag and a .dir suffix. For the other two database types, the file name is followed by .db.

Managing the postmaster Alias

Every system must be able to send mail to a postmaster mailbox. You can create an NIS or NIS+ alias for postmaster, or you can create the alias in each local /etc/mail/aliases file. Refer to these procedures.

• How to Create a postmaster Alias in Each Local /etc/mail/aliases File

• How to Create a Separate Mailbox for postmaster

• How to Add the postmaster Mailbox to the Aliases in the /etc/mail/aliases File

How to Create a postmaster Alias in Each Local /etc/mail/aliases File

If you are creating the postmaster alias in each local /etc/mail/aliases file, follow these instructions.

1. Become superuser on each local system or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. View the /etc/mail/aliases entry.

   # cat /etc/mail/aliases # Following alias is required by the mail protocol, RFC 2821 # Set it to the address of a HUMAN who deals with this system's # mail problems. Postmaster: root

3. Edit each system's /etc/mail/aliases file.

   Change root to the mail address of the person who is designated as the postmaster.

   Postmaster: mail_address

   mail_address

   Use the assigned address for the person who is designated as the postmaster.

4. (Optional) Create a separate mailbox for the postmaster.

   You can create a separate mailbox for the postmaster to keep postmaster mail separate from personal mail. If you create a separate mailbox, use the mailbox address instead of the postmaster's personal mail address when you edit the /etc/mail/aliases files. For details, refer to How to Create a Separate Mailbox for postmaster.

How to Create a Separate Mailbox for postmaster

If you are creating a separate mailbox for postmaster, follow these instructions.

1. Become root on the mail server or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Create a user account for the person who is designated as postmaster and put an asterisk (*) in the password field.

   For details about adding a user account, refer to “Managing User Accounts and Groups (Tasks)” in System Administration Guide: Basic Administration.

3. After mail has been delivered, enable the mail program to read and write to the mailbox name.

   # mail -f postmaster

   postmaster

   Use the assigned address.

How to Add the postmaster Mailbox to the Aliases in the /etc/mail/aliases File

If you are adding a postmaster mailbox to the aliases in the /etc/mail/aliases file, follow these instructions.

1. Become root on each system or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Add an alias for root. Use the mail address of the person who is designated as the postmaster.

   # cat /etc/mail/aliases .. root: user@host.domain.com

   user@host.domain.com

   Use the assigned address of the person who is designated as postmaster.

3. On the postmaster's local system, create an entry in the /etc/mail/aliases file that defines the name of the alias (sysadmin, for example) and include the path to the local mailbox.

   # cat /etc/mail/aliases .. sysadmin: /usr/somewhere/somefile

   sysadmin	Create a name for a new alias.
   /usr/somewhere/somefile	Use the path to the local mailbox.

4. Rebuild the alias database.

   # newaliases

Administering the Queue Directories (Task Map)

The following table describes the procedures for administering the mail queue.

Administering the Queue Directories (Tasks)

This section describes some helpful tasks for queue administration. For information about the client-only queue, refer to New Configuration File, submit.cf. For other related information, you can refer to New Queue Features.

How to Display the Contents of the Mail Queue, /var/spool/mqueue

Use this procedure to see how many messages are in the queue and how fast they are being cleared from the queue.

Use the following command to display this information.

• The queue IDs

• The size of the message

• The date the message entered the queue

• The message status

• The sender and the recipients

# /usr/bin/mailq | more

This command now checks for the authorization attribute, solaris.admin.mail.mailq. If the check is successful, the equivalent of specifying the -bp flag with sendmail is executed. If the check fails, an error message is printed. By default, this authorization attribute is enabled for all users. The authorization attribute can be disabled by modifying the user entry in prof_attr. For more information, refer to the man pages for prof_attr(4) and mailq(1).

How to Force Mail Queue Processing in the Mail Queue, /var/spool/mqueue

Use this procedure, for example, to process messages to a system that was previously unable to receive messages.

1. Become root or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Force queue processing and display the progress of the jobs as the queue is cleared.

   # /usr/lib/sendmail -q -v

How to Run a Subset of the Mail Queue, /var/spool/mqueue

Use this procedure, for example, to force a substring of an address, such as a host name, to be processed or to force a particular message from the queue.

1. Become root or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Run a subset of the mail queue at any time with -qRstring.

   # /usr/lib/sendmail -qRstring

   string

   Use a recipient's alias or a substring (like a host name) of user@host.domain.

   Alternately, you can run a subset of the mail queue with -qInnnnn.

   # /usr/lib/sendmail -qInnnnn

   nnnnn

   Use a queue ID.

How to Move the Mail Queue, /var/spool/mqueue

If you are moving the mail queue, follow these instructions.

1. Become root on the mail host or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Kill the sendmail daemon.

   # /etc/init.d/sendmail stop

   Now sendmail is no longer processing the queue directory.

3. Change to the /var/spool directory.

   # cd /var/spool

4. Move the directory, mqueue, and all its contents to the omqueue directory. Then create a new empty directory that is named mqueue.

   # mv mqueue omqueue; mkdir mqueue

5. Set the permissions of the directory to read/write/execute by owner, and read/execute by group. Also, set the owner and group to daemon.

   # chmod 750 mqueue; chown root:bin mqueue

6. Start sendmail.

   # /etc/init.d/sendmail start

How to Run the Old Mail Queue, /var/spool/omqueue

To run an old mail queue, follow these instructions.

1. Become root or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Run the old mail queue.

   # /usr/lib/sendmail -oQ/var/spool/omqueue -q

   The -oQ flag specifies an alternate queue directory and the -q flag says to run every job in the queue. Use the -v flag if you are displaying the verbose output on the screen.

3. Remove the empty directory.

   # rmdir /var/spool/omqueue

Administering .forward Files (Task Map)

The following table describes the procedures for administering .forward files. For more information, refer to .forward Files in Chapter 26, Mail Services (Reference).

Administering .forward Files (Tasks)

This section contains several procedures that are related to .forward file administration. Because these files can be edited by users, they can cause problems. For more information, refer to .forward Files in Chapter 26, Mail Services (Reference).

How to Disable .forward Files

This procedure, which prevents automated forwarding, disables the .forward file for a particular host.

1. Become root or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Make a copy of /usr/lib/mail/domain/solaris-generic.m4 or your site-specific domain m4 file.

   # cd /usr/lib/mail/domain # cp solaris-generic.m4 mydomain.m4

   mydomain

   Use the file name of your choice.

3. Add the following line to the file you just created.

   define(`confFORWARD_PATH',`')dnl

   If a value for confFORWARD_PATH already exists in the m4 file, replace it with this null value.

4. Build and install a new configuration file.

   If you need help with this step, refer to How to Build a New sendmail.cf File.

How to Change the .forward File Search Path

If, for example, you want to put all .forward files in a common directory, follow these instructions.

1. Become root or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

2. Make a copy of /usr/lib/mail/domain/solaris-generic.m4 or your site-specific domain m4 file.

   # cd /usr/lib/mail/domain # cp solaris-generic.m4 mydomain.m4

   mydomain

   Use the file name of your choice.

3. Add the following line to the file that you just created.

   define(`confFORWARD_PATH',`$z/.forward:/var/forward/$u')dnl

   If a value for confFORWARD_PATH already exists in the m4 file, replace it with this new value.

4. Build and install a new configuration file.

   If you need help with this step, refer to How to Build a New sendmail.cf File.

How to Create and Populate /etc/shells

This file is not included in the standard release, so you must add it if users are to be allowed to use .forward files to forward mail to a program or to a file. You can create the file manually by using grep to identify all of the shells that are listed in your password file. You can then type the shells into the file. However, it is easier to use the following procedure, which employs a script that can be downloaded.

1. Download the script.

   http://www.sendmail.org/vendor/sun/gen-etc-shells.html

2. Become root or assume an equivalent role.

   For information about roles, refer to “Using Privileged Applications” in System Administration Guide: Security Services.

3. To generate a list of shells, run the gen-etc-shells script.

   # ./gen-etc-shells.sh > /tmp/shells

   This script uses the getent command to collect the names of shells that are included in the password file sources that are listed in /etc/nsswitch.conf.

4. Inspect and edit the list of shells in /tmp/shells.

   With the editor of your choice, remove any shells that you are not including.

5. Move the file to /etc/shells.

   # mv /tmp/shells /etc/shells

Troubleshooting Procedures and Tips for Mail Services (Task Map)

The following table describes troubleshooting procedures and tips for mail services.

Troubleshooting Procedures and Tips for Mail Services (Tasks)

This section provides some procedures and tips that you can use for troubleshooting problems with mail services.

How to Test the Mail Configuration

To test the changes you make to your configuration file, follow these instructions.

1. Restart sendmail on any system that has a revised configuration file.

   # pkill -HUP sendmail

2. Send test messages from each system.

   # /usr/lib/sendmail -v names </dev/null

   names

   Specify a recipient's email address.

   This command sends a null message to the specified recipient and displays the message activity on your monitor.

3. Send mail to yourself or other people on the local system by addressing the message to a regular user name.

4. (Optional) If you are connected to a network, send mail in three directions to someone on another system.

   • From the main system to a client system

   • From a client system to the main system

   • From a client system to another client system

5. (Optional) If you have a mail gateway, send mail to another domain from the mail host to ensure that the relay mailer and host are configured properly.

6. (Optional) If you have set up a UUCP connection on your phone line to another host, send mail to someone at that host and have that person send mail back or call you when the message is received.

7. Ask someone to send mail to you over the UUCP connection.

   The sendmail program cannot detect whether the message is delivered because it passes the message to UUCP for delivery.

8. From different systems, send a message to postmaster and ensure that it is delivered to your postmaster's mailbox.

How to Check Mail Aliases

To verify aliases and to confirm that mail can or cannot be delivered to a specified recipient, follow these instructions.

Display the aliases and identify that the final address is deliverable or not deliverable.

% /usr/lib/sendmail -v -bv recipient

The following is an example of the output.

% /usr/lib/sendmail -v -bv sandy
sandy... aliased to ssmith
ssmith... aliased to sandy@phoenix
sandy@phoenix... deliverable: mailer esmtp, host phoenix, user sandy@phoenix.example.com
%

Avoid loops and inconsistent databases when both local and domain-wide aliases are used. Be especially careful when you move a user from one system to another to avoid the creation of alias loops.

How to Test the sendmail Rule Sets

To check the input and returns of the sendmail rule sets, follow these instructions.

1. Change to address test mode.

   # /usr/lib/sendmail -bt

2. Test a mail address.

   Provide the following numbers and address at the last prompt (>).

   > 3,0 mail_address

   mail_address

   Use the mail address that you are testing.

3. End the session.

   Press Control-d.

The following is an example of the output.

% /usr/lib/sendmail -bt
ADDRESS TEST MODE (ruleset 3 NOT automatically invoked)
Enter <ruleset> <address>
> 3,0 sandy@phoenix
canonify           input: sandy @ phoenix
Canonify2          input: sandy < @ phoenix >
Canonify2        returns: sandy < @ phoenix . example . com . >
canonify         returns: sandy < @ phoenix . example . com . >
parse              input: sandy < @ phoenix . example . com . >
Parse0             input: sandy < @ phoenix . example . com . >
Parse0           returns: sandy < @ phoenix . example . com . >
ParseLocal         input: sandy < @ phoenix . example . com . >
ParseLocal       returns: sandy < @ phoenix . example . com . >
Parse1             input: sandy < @ phoenix . example . com . >
MailerToTriple     input: < mailhost . phoenix . example . com > 
     sandy < @ phoenix . example . com . >
MailerToTriple   returns: $# relay $@ mailhost . phoenix . example . com 
     $: sandy < @ phoenix . example . com . >
Parse1           returns: $# relay $@ mailhost . phoenix . example . com 
     $: sandy < @ phoenix . example . com . >
parse            returns: $# relay $@ mailhost . phoenix . example . com 
     $: sandy < @ phoenix . example . com . >

How to Verify Connections to Other Systems

The mconnect program opens a connection to a mail server on a host that you specify and enables you to test that connection. The program runs interactively, so you can issue various diagnostic commands. See the mconnect(1) man page for a complete description. The following example verifies that mail to the user name sandy is deliverable.

% mconnect phoenix

connecting to host phoenix (172.31.255.255), port 25
connection open
220 phoenix.example.com ESMTP Sendmail 8.12.0+Sun/8.12.0; Sun, 4 Sep 2001 3:52:56 -0700(PDT)
expn sandy
250 2.1.5 <sandy@phoenix.example.com>
quit

If you cannot use mconnect to connect to an SMTP port, check these conditions.

• Is the system load too high?

• Is the sendmail daemon running?

• Does the system have the appropriate /etc/mail/sendmail.cf file?

• Is port 25 (the port that sendmail uses) active?

Logging Error Messages

Your mail services logs most error messages by using the syslogd program. By default, the syslogd program sends these messages to a system that is called loghost, which is specified in the /etc/hosts file. You can define loghost to hold all logs for an entire NIS domain. If no loghost is specified, error messages from syslogd are not reported.

The /etc/syslog.conf file controls where the syslogd program forwards messages. You can change the default configuration by editing the /etc/syslog.conf file. You must restart the syslog daemon for any changes to become active. To gather information about mail, you can add the following selections to the file.

• mail.alert – Messages about conditions that should be fixed now

• mail.crit – Critical messages

• mail.warning – Warning messages

• mail.notice – Messages that are not errors, but might need attention

• mail.info – Informational messages

• mail.debug – Debugging messages

The following entry in the /etc/syslog.conf file sends a copy of all critical, informational, and debug messages to /var/log/syslog.

mail.crit;mail.info;mail.debug			/var/log/syslog

Each line in the system log contains a timestamp, the name of the system that generated the line, and a message. The syslog file can log a large amount of information.

The log is arranged in a succession of levels. At the lowest level, only unusual occurrences are logged. At the highest level, even the most mundane and uninteresting events are recorded. As a convention, log levels under 10 are considered “useful.” Log levels higher than 10 are usually used for debugging. See the “Customizing System Message Logging” in System Administration Guide: Advanced Administration for information about loghost and the syslogd program.

Other Sources for Mail Diagnostic Information

For other diagnostic information, check the following sources.

• Look at the Received lines in the header of the message. These lines trace the route the message took as it was relayed. Remember to consider time–zone differences.

• Look at the messages from MAILER-DAEMON. These messages typically report delivery problems.

• Check the system log that records delivery problems for your group of systems. The sendmail program always records its activities in the system log. You might want to modify the crontab file to run a shell script nightly that searches the log for SYSERR messages and mails any messages that it finds to the postmaster.

• Use the mailstats program to test mail types and determine the number of incoming and outgoing messages.

Resolving Error Messages

This section describes how you can resolve some sendmail–related error messages that are in the Solaris 9 operating environment. You can also refer to http://www.sendmail.org/faq/.

The following error messages contain two or more of the following types of information.

• Cause: What might have happened to cause the message

• Description: What the user was doing when the error message occurred

• Action: What you can do to fix the problem or to continue with your work

• Technical Notes: Background information that might be interesting or helpful to a technical audience, such as developers

• See Also: Suggests further reading

451 timeout waiting for input during source

Cause: When sendmail reads from any source that might time out, such as an SMTP connection, it sets a timer to the value of various Timeout options before reading begins. If the read is not completed before the timer expires, this message appears and reading stops. (Usually this situation occurs during RCPT.) The mail message is then queued for later delivery.

Action: If you see this message often, increase the value of various Timeout options in the /etc/mail/sendmail.cf file. If the timer is already set to a large number, look for hardware problems, such as poor network cabling or connections.

See Also: For more information about the Timeout option, refer to Changes to the Timeout Option. If you are using online documentation, the term “timeouts” is a good search string.

550 hostname... Host unknown

Cause: This sendmail message indicates that the destination host machine, which is specified by the portion of the address after the at sign (@), was not found during domain name system (DNS) lookup.

Action: Use the nslookup command to verify that the destination host exists in that domain or other domains, perhaps with a slightly different spelling. Otherwise, contact the intended recipient and ask for a proper address.

550 username... User unknown

Cause: This sendmail message indicates that the intended recipient, who is specified by the portion of the address before the at sign (@), could not be located on the destination host machine.

Action: Check the email address and try again, perhaps with a slightly different spelling. If this remedy does not work, contact the intended recipient and ask for a proper address.

554 hostname... Local configuration error

Cause: This sendmail message usually indicates that the local host is trying to send mail to itself.

Action: Check the value of the $j macro in the /etc/mail/sendmail.cf file to ensure that this value is a fully qualified domain name.

Technical Notes: When the sending system provides its host name to the receiving system (in the SMTP HELO command), the receiving system compares its name to the sender's name. If these names are the same, the receiving system issues this error message and closes the connection. The name that is provided in the HELO command is the value of the $j macro.

See Also: For additional information, refer to http://www.sendmail.org/faq/section4.html#4.5.

config error: mail loops back to myself.

Cause: If you set up an MX record and make host bar the mail exchanger for domain foo, but you do not configure host bar to know that it is the mail exchanger for domain foo, you receive this error message.

Also, another possibility is that both the sending system and the receiving system are identifying as the same domain.

Action: For instructions, refer to http://www.sendmail.org/faq/section4.html#4.5.

host name configuration error

Action: Follow the instructions that were provided for resolving this error message, 554 hostname... Local configuration error.

Technical Notes: This is an old sendmail message, which replaced I refuse to talk to myself and is now replaced by the Local configuration error message.

user unknown

Description: When you try to send mail to a user, the error Username... user unknown is displayed. The user is on the same system.

Action: Check for a typographical error in the entered email address. Otherwise, the user could be aliased to a nonexistent email address in /etc/mail/aliases or in the user's .mailrc file. Also, check for uppercase characters in the user name. Preferably, email addresses should not be case sensitive.

See Also: For additional information, refer to http://www.sendmail.org/faq/section4.html#4.17.