OPS235 Assignment 2 Tips

Turning Firewall On/Off on CentOS 7

To turn it off

• /usr/sbin/iptables -F
• /usr/sbin/iptables -P INPUT ACCEPT
• /usr/sbin/iptables -P OUTPUT ACCEPT

To turn it on

• systemctl restart firewalld.service

Turning SELinux On/Off on CentOS 7

To turn off SELinux temporary into permissive mode

• setenforce 0

To turn SELinx back on from permissive mode

• setenforce 1

To check the current status of SELinux

• sestatus

SELinux status:                 enabled
SELinuxfs mount:                /sys/fs/selinux
SELinux root directory:         /etc/selinux
Loaded policy name:             targeted
Current mode:                   enforcing
Mode from config file:          enforcing
Policy MLS status:              enabled
Policy deny_unknown status:     allowed
Max kernel policy version:      28

• setenforce 0
• sestatus

SELinux status:                 enabled
SELinuxfs mount:                /sys/fs/selinux
SELinux root directory:         /etc/selinux
Loaded policy name:             targeted
Current mode:                   permissive
Mode from config file:          enforcing
Policy MLS status:              enabled
Policy deny_unknown status:     allowed
Max kernel policy version:      28

Listing the RUN-TIME configurable parameter for SELinux

• getsebool -a

abrt_anon_write --> off
abrt_handle_event --> off
abrt_upload_watch_anon_write --> on
antivirus_can_scan_system --> off
antivirus_use_jit --> off
auditadm_exec_content --> on
authlogin_nsswitch_use_ldap --> off
authlogin_radius --> off
authlogin_yubikey --> off
awstats_purge_apache_log_files --> off
boinc_execmem --> on
...

List of SELinux run-time configurable parameter that control Apache server (httpd)

• getsebool -a | grep httpd

httpd_anon_write --> off
httpd_builtin_scripting --> on
httpd_can_check_spam --> off
httpd_can_connect_ftp --> off
httpd_can_connect_ldap --> off
httpd_can_connect_mythtv --> off
httpd_can_connect_zabbix --> off
httpd_can_network_connect --> off
httpd_can_network_connect_cobbler --> off
httpd_can_network_connect_db --> off
httpd_can_network_memcache --> off
httpd_can_network_relay --> off
httpd_can_sendmail --> off
httpd_dbus_avahi --> off
httpd_dbus_sssd --> off
httpd_dontaudit_search_dirs --> off
httpd_enable_cgi --> on
httpd_enable_ftp_server --> off
httpd_enable_homedirs --> off
httpd_execmem --> off
httpd_graceful_shutdown --> on
httpd_manage_ipa --> off
httpd_mod_auth_ntlm_winbind --> off
httpd_mod_auth_pam --> off
httpd_read_user_content --> off
httpd_run_preupgrade --> off
httpd_run_stickshift --> off
httpd_serve_cobbler_files --> off
httpd_setrlimit --> off
httpd_ssi_exec --> off
httpd_sys_script_anon_write --> off
httpd_tmp_exec --> off
httpd_tty_comm --> off
httpd_unified --> off
httpd_use_cifs --> off
httpd_use_fusefs --> off
httpd_use_gpg --> off
httpd_use_nfs --> off
httpd_use_openstack --> off
httpd_use_sasl --> off
httpd_verify_dns --> off

How to turn on/off a SELinux run-time parameter

To turn on a run-time parameter

For Current session

• setsebool httpd_can_network_connect_db on

For good (even after a reboot)

• setsebool -P httpd_can_network_connect_db on

To turn off a run-time parameter

For the current session

• setsebool httpd_can_network_connect_db off

For good (even after a reboot)

• setsebool -P httpd_can_network_connect_db off