Red Hat System Administration II

Instructions

1. Log in to the servera machine as the student user and switch to the root user.

   [student@workstation ~]$ ssh student@servera
   ...output omitted...
   [student@servera ~]$ sudo -i
   [sudo] password for student: student
   [root@servera ~]#

2. Use the grep command to find the GID and UID for the postfix and postdrop groups and users. To do so, use the rpm -q --scripts command, which queries the information for a specific package and shows the scripts that are used as part of the installation process.

   [root@servera ~]# rpm -q --scripts postfix | grep -e 'user' -e 'group'
   # Add user and groups if necessary
   # generated from postfix.sysusers
   getent group 'postfix' >/dev/null || groupadd -f -g '89' -r 'postfix' || :
           useradd -r -u '89' -g 'postfix' -d '/var/spool/postfix' -s '/sbin/nologin' -c '' 'postfix' || :
           useradd -r -g 'postfix' -d '/var/spool/postfix' -s '/sbin/nologin' -c '' 'postfix' || :
   getent group 'postdrop' >/dev/null || groupadd -f -g '90' -r 'postdrop' || :
   getent group 'mail' >/dev/null || groupadd -f -g '12' -r 'mail' || :
   getent group 'mail' >/dev/null || groupadd -r 'mail' || :
       useradd -r -g 'postfix' -d '/' -s '/usr/sbin/nologin' -c '' 'postfix' || :
   if getent group 'mail' >/dev/null; then
       usermod -a -G 'mail' 'postfix' || :
           setgid_group=postdrop \

3. Modify the previous regular expression to display the first two messages in the /var/log/maillog file. In this search, you do not need to use the caret character (^), because you are not searching for the first character in a line.

   [root@servera ~]# grep 'postfix' /var/log/maillog | head -n 2
   Apr  1 15:27:16 servera postfix/postfix-script[3121]: starting the Postfix mail system
   Apr  1 15:27:16 servera postfix/master[3123]: daemon started -- version 3.5.9, configuration /etc/postfix

4. Find the name of the queue directory for the Postfix server. Search the /etc/postfix/main.cf configuration file for all information about queues. Use the grep command -i option to ignore case distinctions.

   [root@servera ~]# grep -i 'queue' /etc/postfix/main.cf
   # testing.  When soft_bounce is enabled, mail will remain queued that
   # The queue_directory specifies the location of the Postfix queue.
   queue_directory = /var/spool/postfix
   # QUEUE AND PROCESS OWNERSHIP
   # The mail_owner parameter specifies the owner of the Postfix queue
   # is the Sendmail-compatible mail queue listing command.
   # setgid_group: The group for mail submission and queue management

5. Confirm that the postfix service writes messages to the /var/log/messages file. Use the less command and then the slash character (/) to search the file. Press n to move to the next entry that matches the search. Press q to quit the less command.

   [root@servera ~]# less /var/log/messages
   ...output omitted...
   Apr  1 15:27:15 servera systemd[1]: Starting Postfix Mail Transport Agent...
   ...output omitted...
   Apr  1 15:27:16 servera systemd[1]: Started Postfix Mail Transport Agent.
   ...output omitted...
   /Postfix

6. Use the ps aux command to confirm that the postfix server is currently running. Use the grep command to limit the output to the necessary lines.

   [root@servera ~]# ps aux | grep postfix
   root        3123  0.0  0.2  38172  4384 ?        Ss   15:27   0:00 /usr/libexec/postfix/master -w
   postfix     3124  0.0  0.4  45208  8236 ?        S    15:27   0:00 pickup -l -t unix -u
   postfix     3125  0.0  0.4  45252  8400 ?        S    15:27   0:00 qmgr -l -t unix -u
   root        3228  0.0  0.1 221668  2288 pts/0    S+   15:55   0:00 grep --color=auto postfix

7. Confirm that the qmgr, cleanup, and pickup queues are correctly configured. Use the grep command -e option to match multiple entries in the same file. The /etc/postfix/master.cf file is the configuration file.

   [root@servera ~]# grep -e qmgr -e pickup -e cleanup /etc/postfix/master.cf
   pickup    unix  n       -       n       60      1       pickup
   cleanup   unix  n       -       n       -       0       cleanup
   qmgr      unix  n       -       n       300     1       qmgr
   #qmgr     unix  n       -       n       300     1       oqmgr

8. Return to the workstation machine as the student user.

   [root@servera ~]# exit
   logout
   [student@servera ~]$ exit
   logout
   Connection to servera closed.
   [student@workstation ~]$