"How To" Guides for UNIX System Administration

Outgoing Mail Administration

Aliases and Distribution Lists
Aliases and distribution lists can be maintained by updating the `/etc/mail/aliases` file. After making any changes, rebuild the alias database with this command: `sendmail -bi` Be sure to resolve any warnings or errors, since even warnings can prevent the aliases from being processed. back to top

Aliases and distribution lists can be maintained by updating the /etc/mail/aliases file. After making any changes, rebuild the alias database with this command:


                  sendmail -bi

Be sure to resolve any warnings or errors, since even warnings can prevent the aliases from being processed.

SMTP Configuration
Outgoing SMTP e-mail is handled by `sendmail`. The configuration is stored in `/etc/sendmail.cf`, which may be a symbolic link to `/etc/mail/sendmail.cf`. Refresh the configuration after making any changes: `refresh -s sendmail` back to top

SMTP Configuration

Outgoing SMTP e-mail is handled by sendmail. The configuration is stored in /etc/sendmail.cf, which may be a symbolic link to /etc/mail/sendmail.cf. Refresh the configuration after making any changes:


                  refresh -s sendmail

Test Outgoing E-mail
Outgoing e-mail can be tested by creating a test file with the message, including SMTP headers, and then routing it with: `sendmail -t < mymsg.txt` An even more granular test can be performed using telnet: `telnet smtp.ExampleOnly.com 25 HELO client.ExampleOnly.com MAIL From: First.Last@ExampleOnly.com RCPT To: Someone.Else@ExampleOnly.com DATA To: Someone.Else@ExampleOnly.com From: First.Last@ExampleOnly.com Subject: My test message Here is my message. . QUIT` If the `RCPT` command responds with Relaying denied then the sending host needs to be included as one of the trusted host names specified by the `w` class (`Cw`) in the sendmail SMTP configuration or added to the list in the file referenced by the `Fw...` line there (possibly `/etc/mail/local-host-names`). back to top

Test Outgoing E-mail

Outgoing e-mail can be tested by creating a test file with the message, including SMTP headers, and then routing it with:


                  sendmail -t < mymsg.txt

An even more granular test can be performed using telnet:


                  telnet smtp.ExampleOnly.com 25
                  

                  HELO client.ExampleOnly.com
                  

                  MAIL From: First.Last@ExampleOnly.com
                  

                  RCPT To: Someone.Else@ExampleOnly.com
                  

                  DATA
                  

                  To: Someone.Else@ExampleOnly.com
                  

                  From: First.Last@ExampleOnly.com
                  

                  Subject: My test message
                  

                  Here is my message.
                  

                  .
                  

                  QUIT

If the RCPT command responds with Relaying denied then the sending host needs to be included as one of the trusted host names specified by the w class (Cw) in the sendmail SMTP configuration or added to the list in the file referenced by the Fw... line there (possibly /etc/mail/local-host-names).

Allow Mail Relay To/From Specific Hosts
To allow mail relay to specific domains on the local host, create a file named `local-host-names` in the `/etc/mail` directory containing the list of domains that are hosted on the local machine. To allow mail relay from specific host names, create a file named `relay-domains` in the `/etc/mail` directory containing the list of host names that are allowed to send mail. back to top

Allow Mail Relay To/From Specific Hosts

To allow mail relay to specific domains on the local host, create a file named local-host-names in the /etc/mail directory containing the list of domains that are hosted on the local machine.

To allow mail relay from specific host names, create a file named relay-domains in the /etc/mail directory containing the list of host names that are allowed to send mail.

Last updated Monday April 16, 2007

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