Email: postfix-exercise2.txt

REMOTE MAIL CONFIGURATION
-------------------------

1. Let's configure our postfix to accept mail for our newly created domain!

    * First, find out what domains postfix is already configured
      to accept:

    # postconf -d mydestination

      You should see:

    mydestination = $myhostname, localhost.$mydomain, localhost

    * Let's add our domain -- the one we created in the DNS delegation exercises
      For example, if your domain is "phil":

    # cd /usr/local/etc/postfix/
    # postconf -e mydestination='$myhostname, localhost.$mydomain, localhost, phil.ws3.conference.sanog.org'

    (of course, use your own domain here, NOT phil!)

    * View the contents of main.cf, and make sure that the new configuration
      for "mydestination" is there:

    # tail main.cf
    ...
    mydestination = $myhostname, localhost.$mydomain, localhost, phil.ws3.conference.sanog.org

    * Tell postfix to reload the configuration

    # postfix reload

2. Send an email to the user "sanog" at your domain:

    # echo "test to my new domain" | mail sanog@phil.ws3.conference.sanog.org

    # tail /var/log/maillog

    * As "sanog":

    $ mutt

    * Check that the mail has arrived in your mailbox

3. Reconfigure your DNS so that you have an MX for your domain.

    * If your domain is called "YOURDOMAIN" (YOURDOMAIN.ws3.conference.sanog.org),
      and your PC/WS is "ws15", then, add the following to your
      /etc/namedb/master/YOURDOMAIN.ws3.conference.sanog.org,

      (for example, after the NS records)

        ...
        NS      ws15.ws3.conference.sanog.org.
        NS      ws16.ws3.conference.sanog.org.

        MX  10  ws15.ws3.conference.sanog.org.      ; <<<- MX for mail
        ...

    * MAKE SURE that you are pointing to YOUR ws and not someone else's!

    * REMEMBER THE SERIAL!

    * Reload your zone (rndc reload ...)

4. Use dig to verify that you have configured the DNS correctly:

    # dig @wsXX MX YOURDOMAIN.ws3.conference.sanog.org

    (where XX is your own WS, but also the slaves of your zone!)

    * Is your MX published ?
    * Do your slaves have the MX as well ?

5. You still need to tell Postfix to use your new domain name as its
   Origin -- meaning, what the mails coming out will have after @:

   * edit main.cf

   myorigin = YOURDOMAIN.$mydomain

   ... $mydomain is always "ws3.conference.sanog.org" (if your hostname
   is set correctly)

   * Now reload postfix

   # postfix reload

6. Send mail to others

        # echo "hello from here" | mail -s "hello from YOURDOMAIN" sanog@THEIRDOMAIN.ws3.conference.sanog.org
        (THEIRDOMAIN = someone else's domain in the room)

        * Check that they receive your mail AND that the email they see from you is:

        sanog@YOURDOMAIN.ws3.conference.sanog.org
        
6. Now, ask others to send mail to "sanog@YOURDOMAIN.ws3.conference.sanog.org"

    # echo "hello from there" | mail -s "hello from THEIRDOMAIN" sanog@YOURDOMAIN.ws3.conference.sanog.org

7. Check that you are receiving the mail in your sanog account:

    $ mutt

8. Try and send mail to sanog@YOURDOMAIN.ws3.conference.sanog.org from the
   rest of the world (GMAIL, Hotmail, ...)