LDAP works with PHP CLI but not through apache

Question

I'm trying to authenticate over LDAP against a Windows 2008 Server from a Fedora box.

The following code works from the command line (prints "Success"):

if($ldap = ldap_connect('10.0.0.101'))
{
  ldap_set_option($ldap, LDAP_OPT_PROTOCOL_VERSION, 3);
  $bind = ldap_bind($ldap,'[email protected]','XXXXXXX');
  print ldap_error($ldap);
}

...pulling the same file via Apache/mod_php prints "Can't contact LDAP server"

I've seen a lot of reports of issues like this, but no useful information on how to resolve it.

I had the same problem yesterday on Ubuntu 18.04 with the stock Apache, PHP 7.2, LDAP and libsasl2-modules-gssapi-mit, but only with LDAPS not LDAP, and it is gone now, and I can't tell you what made it go away :-( — reinierpost

cyberswat cyberswat · Accepted Answer · 2013-02-27T17:06:38

I just fought this exact problem for a long time on centos6. The php.ini difference seem like a good place to check, but it didn't give me the answer. It turns out this was related to SELinux.

$ getsebool -a | grep httpd
allow_httpd_anon_write --> off
allow_httpd_mod_auth_ntlm_winbind --> off
allow_httpd_mod_auth_pam --> off
allow_httpd_sys_script_anon_write --> off
httpd_builtin_scripting --> on
httpd_can_check_spam --> off
httpd_can_network_connect --> off
httpd_can_network_connect_cobbler --> off
httpd_can_network_connect_db --> on
httpd_can_network_memcache --> on
httpd_can_network_relay --> off
httpd_can_sendmail --> off
httpd_dbus_avahi --> on
httpd_enable_cgi --> on
httpd_enable_ftp_server --> off
httpd_enable_homedirs --> off
httpd_execmem --> off
httpd_manage_ipa --> off
httpd_read_user_content --> off
httpd_run_stickshift --> off
httpd_setrlimit --> off
httpd_ssi_exec --> off
httpd_tmp_exec --> off
httpd_tty_comm --> on
httpd_unified --> on
httpd_use_cifs --> off
httpd_use_gpg --> off
httpd_use_nfs --> off
httpd_use_openstack --> off
httpd_verify_dns --> off

You'll note, that in my case, httpd_can_network_connect was set to off. This is a boolean in SELinux and can be adjusted with the following command.

$ setsebool -P httpd_can_network_connect on

You can read more about this at http://wiki.centos.org/TipsAndTricks/SelinuxBooleans which explicitly uses the case of apache and ldap as an example. Hope it helps!

LDAP works with PHP CLI but not through apache

2 Answers