I need to secure my LDAP server and am not quite sure the best way to go about it. I am running Debian "Lenny", and using OpenLDAP (slapd).

I notice that if I run:

ldapsearch -x -W -b 'dc=example,dc=com' -H 'ldap://' 'objectclass=*'

and just press ENTER when it prompts for a password, that I get a list of directory entries. Anonymous access is not acceptable if I am opening this up to the internet, but cannot find a way to disable anonymous access.

I have tried modifying /etc/ldap/slapd.conf to the following:

access to *
    by dn="cn=admin,dc=example,dc=com" write
    by * none

... but that doesn't do the trick.

After this, I will get it running over TLS, but it is pointless doing that step while still allowing anonymous access.

Any ideas?

  • TLS is not completely pointless. It also allows securing passwords for non-anonymous binds, and making sure it's really your LDAP server you're connecting to.
    – user1686
    Sep 10, 2009 at 4:42

3 Answers 3


To completely disable anonymous bind, add this line to slapd.conf:

disallow bind_anon

and restart the slapd service.

  • For FreeBSD: This line "disallow bind_anon" should be added in the global section. Adding at the bottom did not work for me. freebsd.org/cgi/…
    – sunil_rbc
    Jun 1 at 7:51

If the accepted answer does not work for you (it didn't for me on Ubuntu), try the following.

Create ldiff file:

nano /usr/share/slapd/ldap_disable_bind_anon.ldif

Paste in this:

dn: cn=config
changetype: modify
add: olcDisallows
olcDisallows: bind_anon

dn: cn=config
changetype: modify
add: olcRequires
olcRequires: authc

dn: olcDatabase={-1}frontend,cn=config
changetype: modify
add: olcRequires
olcRequires: authc

And then run:

ldapadd -Y EXTERNAL -H ldapi:/// -f /usr/share/slapd/ldap_disable_bind_anon.ldif
  • 1
    works on ubuntu!!
    – RPB
    Feb 26, 2019 at 6:51
  • Are the 1st and 3rd ones actually required?
    – Al Klimov
    Jan 16 at 13:38

Since you are planning to go SSL/TLS soon, you may want to consider using client certificate verification to further tighten your security. Stunnel with -v -A options would do nicely.

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