RHCSA Rapid Track

Instructions

Your company decided to run a new web application. This application listens on the 80/TCP and 1001/TCP ports. All changes that you make must persist across a reboot.

1. From the workstation machine, test access to the default web server at http://serverb.lab.example.com and to the http://serverb.lab.example.com:1001 virtual host.

   1. Test access to the http://serverb.lab.example.com web server. The test currently fails. The web server should return SERVER B.

      [student@workstation ~]$ curl http://serverb.lab.example.com
      curl: (7) Failed to connect to serverb.lab.example.com port 80: Connection refused

   2. Test access to the http://serverb.lab.example.com:1001 virtual host. The test currently fails. The virtual host should return VHOST 1.

      [student@workstation ~]$ curl http://serverb.lab.example.com:1001
      curl: (7) Failed to connect to serverb.lab.example.com port 1001: No route to host

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2. Log in to the serverb machine to determine what is preventing access to the web servers.

   1. Log in to the serverb machine as the student user.

      [student@workstation ~]$ ssh student@serverb
      ...output omitted...
      [student@serverb ~]$

   2. Determine whether the httpd service is active.

      [student@serverb ~]$ systemctl is-active httpd
      inactive

   3. Enable and start the httpd service. The httpd service fails to start.

      [student@serverb ~]$ sudo systemctl enable --now httpd
      [sudo] password for student: student
      Created symlink /etc/systemd/system/multi-user.target.wants/httpd.service → /usr/lib/systemd/system/httpd.service.
      Job for httpd.service failed because the control process exited with error code.
      See "systemctl status httpd.service" and "journalctl -xeu httpd.service" for details.

   4. Investigate why the httpd service fails to start.

      [student@serverb ~]$ systemctl status httpd.service
      × httpd.service - The Apache HTTP Server
           Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled; vendor preset: disabled)
           Active: failed (Result: exit-code) since Wed 2022-04-13 06:55:01 EDT; 2min 52s ago
             Docs: man:httpd.service(8)
          Process: 1640 ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND (code=exited, status=1/FAILURE)
         Main PID: 1640 (code=exited, status=1/FAILURE)
           Status: "Reading configuration..."
              CPU: 31ms
      
      Apr 13 06:55:01 serverb.lab.example.com systemd[1]: Starting The Apache HTTP Server...
      Apr 13 06:55:01 serverb.lab.example.com httpd[1640]: (13)Permission denied: AH00072: make_sock: could not bind to address [::]:1001
      Apr 13 06:55:01 serverb.lab.example.com httpd[1640]: (13)Permission denied: AH00072: make_sock: could not bind to address 0.0.0.0:1001
      Apr 13 06:55:01 serverb.lab.example.com httpd[1640]: no listening sockets available, shutting down
      Apr 13 06:55:01 serverb.lab.example.com httpd[1640]: AH00015: Unable to open logs
      Apr 13 06:55:01 serverb.lab.example.com systemd[1]: httpd.service: Main process exited, code=exited, status=1/FAILURE
      Apr 13 06:55:01 serverb.lab.example.com systemd[1]: httpd.service: Failed with result 'exit-code'.
      Apr 13 06:55:01 serverb.lab.example.com systemd[1]: Failed to start The Apache HTTP Server.

   5. Check whether SELinux is blocking the httpd service from binding to the 1001/TCP port.

      [student@serverb ~]$ sudo sealert -a /var/log/audit/audit.log
      100% done
      found 1 alerts in /var/log/audit/audit.log
      --------------------------------------------------------------------------------
      
      SELinux is preventing /usr/sbin/httpd from name_bind access on the tcp_socket port 1001.
      
      *****  Plugin bind_ports (99.5 confidence) suggests   ************************
      
      If you want to allow /usr/sbin/httpd to bind to network port 1001
      Then you need to modify the port type.
      Do
      # semanage port -a -t PORT_TYPE -p tcp 1001
          where PORT_TYPE is one of the following: http_cache_port_t, http_port_t, jboss_management_port_t, jboss_messaging_port_t, ntop_port_t, puppet_port_t.
      
      *****  Plugin catchall (1.49 confidence) suggests   **************************
      ...output omitted...

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3. Configure SELinux to allow the httpd service to listen on the 1001/TCP port.

   1. Use the semanage command to find the correct port type.

      [student@serverb ~]$ sudo semanage port -l | grep 'http'
      http_cache_port_t              tcp      8080, 8118, 8123, 10001-10010
      http_cache_port_t              udp      3130
      http_port_t                    tcp      80, 81, 443, 488, 8008, 8009, 8443, 9000
      pegasus_http_port_t            tcp      5988
      pegasus_https_port_t           tcp      5989

   2. Bind the 1001/TCP port to the http_port_t type.

      [student@serverb ~]$ sudo semanage port -a -t http_port_t -p tcp 1001

   3. Confirm that the 1001/TCP port is bound to the http_port_t port type.

      [student@serverb ~]$ sudo semanage port -l | grep '^http_port_t'
      http_port_t            tcp      1001, 80, 81, 443, 488, 8008, 8009, 8443, 9000

   4. Enable and start the httpd service.

      [student@serverb ~]$ sudo systemctl enable --now httpd

   5. Verify the running state of the httpd service.

      [student@serverb ~]$ systemctl is-active httpd
      active
      [student@serverb ~]$ systemctl is-enabled httpd
      enabled

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

      [student@serverb ~]$ exit
      logout
      Connection to serverb closed.
      [student@workstation ~]$

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4. From workstation, test again access to the default web server at http://serverb.lab.example.com and to the http://serverb.lab.example.com:1001 virtual host.

   1. Test access to the http://serverb.lab.example.com web server. The web server should return SERVER B.

      [student@workstation ~]$ curl http://serverb.lab.example.com
      SERVER B

   2. Test access to the http://serverb.lab.example.com:1001 virtual host. The test continues to fail.

      [student@workstation ~]$ curl http://serverb.lab.example.com:1001
      curl: (7) Failed to connect to serverb.lab.example.com port 1001: No route to host

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5. Log in to the serverb machine to determine whether the correct ports are assigned to the firewall.

   1. Log in to the serverb machine as the student user.

      [student@workstation ~]$ ssh student@serverb
      ...output omitted...
      [student@serverb ~]$

   2. Verify that the default firewall zone is set to the public zone.

      [student@serverb ~]$ firewall-cmd --get-default-zone
      public

   3. If the previous step does not return public as the default zone, then correct it with the following command:

      [student@serverb ~]$ sudo firewall-cmd --set-default-zone public

   4. Determine the open ports that are listed in the public network zone.

      [student@serverb ~]$ sudo firewall-cmd --zone=public --list-all
      [sudo] password for student: student
      public
        target: default
        icmp-block-inversion: no
        interfaces:
        sources:
        services: cockpit dhcpv6-client http ssh
        ports:
        protocols:
        forward: yes
        masquerade: no
        forward-ports:
        source-ports:
        icmp-blocks:
        rich rules:

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6. Add the 1001/TCP port to the permanent configuration for the public network zone. Confirm your configuration.

   1. Add the 1001/TCP port to the public network zone.

      [student@serverb ~]$ sudo firewall-cmd --permanent --zone=public \
      --add-port=1001/tcp
      success

   2. Reload the firewall configuration.

      [student@serverb ~]$ sudo firewall-cmd --reload
      success

   3. Verify your configuration.

      [student@serverb ~]$ sudo firewall-cmd --zone=public --list-all
      public
        target: default
        icmp-block-inversion: no
        interfaces:
        sources:
        services: cockpit dhcpv6-client http ssh
        ports: 1001/tcp
        protocols:
        forward: yes
        masquerade: no
        forward-ports:
        source-ports:
        icmp-blocks:
        rich rules:

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

      [student@serverb ~]$ exit
      logout
      Connection to serverb closed.
      [student@workstation ~]$

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7. From workstation, confirm that the default web server at http://serverb.lab.example.com returns SERVER B, and that the virtual host at http://serverb.lab.example.com:1001 returns VHOST 1.

   1. Test access to the http://serverb.lab.example.com web server.

      [student@workstation ~]$ curl http://serverb.lab.example.com
      SERVER B

   2. Test access to the http://serverb.lab.example.com:1001 virtual host.

      [student@workstation ~]$ curl http://serverb.lab.example.com:1001
      VHOST 1

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