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--- technical:fr-ldap [2026/07/24 10:28] – [Sign the request] system
+++ technical:fr-ldap [2026/07/26 18:39] (current) – [Configure OpenLDAP for ldaps] system
@@ Line 349: / Line 349: @@
     * **ldap.crt**  - The LDAP public file
+  * Everything is now in place in terms of our PKI for us to configure slapd (OpenLDAP) to support ldaps.
+===== Configure OpenLDAP for ldaps =====
+  * Issue the following commands
+<code bash>
+sudo mkdir /etc/ldap/tls
+#Copy the following files over
+sudo cp ca.crt ldap.key ldap.crt /etc/ldap/tls
+#Change their permissions
+sudo chown openldap:openldap /etc/ldap/tls/*
+sudo chmod 600 /etc/ldap/tls/ldap.key
+sudo chmod 644 /etc/ldap/tls/*.crt
+</code>
+  * Configure slapd to use those files.
+  * Create **tls.ldif** with the following contents
+<code>
+dn: cn=config
+changetype: modify
+replace: olcTLSCertificateFile
+olcTLSCertificateFile: /etc/ldap/tls/ldap.crt
+-
+replace: olcTLSCertificateKeyFile
+olcTLSCertificateKeyFile: /etc/ldap/tls/ldap.key
+-
+replace: olcTLSCACertificateFile
+olcTLSCACertificateFile: /etc/ldap/tls/ca.crt
+</code>
+  * Apply it to the directory with the following commnand:
+<code>
+sudo ldapmodify -Y EXTERNAL -H ldapi:/// -f tls.ldif
+</code>
+  * Enable LDAPS by editing **/etc/default/slapd**.
+  * Look for the following section and change accordingly:
+<code bash>
+# slapd normally serves ldap only on all TCP-ports 389. slapd can also
+# service requests on TCP-port 636 (ldaps) and requests via unix
+# sockets.
+# Example usage:
+# SLAPD_SERVICES="ldap://127.0.0.1:389/ ldaps:/// ldapi:///"
+#SLAPD_SERVICES="ldap:/// ldapi:///"
+SLAPD_SERVICES="ldap:/// ldapi:/// ldaps:///"
+</code bash>
+  * Restart **slapd**.
+<code>
+sudo systemctl restart slapd
+</code>
+  * Confirm that it is now listening on port 636 also:
+<code bash>
+sudo ss -lnpt | grep 636
+LISTEN 0      2048         0.0.0.0:636        0.0.0.0:*    users:(("slapd",pid=698775,fd=11))
+LISTEN 0      2048            [::]:636           [::]:*    users:(("slapd",pid=698775,fd=12))
+</code>
+  * To make the cert's FQDN work smooth add it to the /etc/hosts file (ldap.radiusdesk.com in our case).
+<code>
+.0.0.1 localhost
+.0.1.1 xubuntu-24-4
+.0.0.1 ldap.radiusdesk.com
+# The following lines are desirable for IPv6 capable hosts
+::1     ip6-localhost ip6-loopback
+fe00::0 ip6-localnet
+ff00::0 ip6-mcastprefix
+ff02::1 ip6-allnodes
+ff02::2 ip6-allrouters
+</code>
+  * Test the certificate with the following command:
+<code>
+openssl s_client -connect ldap.radiusdesk.com:636 -CAfile ca.crt
+#IT should end with something like this:
+---
+SSL handshake has read 3905 bytes and written 401 bytes
+Verification: OK
+---
+New, TLSv1.3, Cipher is TLS_AES_256_GCM_SHA384
+Server public key is 4096 bit
+Secure Renegotiation IS NOT supported
+Compression: NONE
+Expansion: NONE
+No ALPN negotiated
+Early data was not sent
+Verify return code: 0 (ok)
+</code>
+  * You can now test with the ldapsearch utility.
+<WRAP center round important>
+Important is to specify the CA cert (LDAPTLS_CACERT) that ldapsearch needs to use else if **will fail**.
+</WRAP>
+<code>
+LDAPTLS_CACERT=/etc/ldap/tls/ca.crt ldapsearch -H ldaps://ldap.radiusdesk.com -x -D "cn=admin,dc=radiusdesk,dc=com" -w testing123 -b dc=radiusdesk,dc=com
+</code>
+<WRAP center round tip>
+  * If you want this CA to be part of the list of trusted CA's on the system you can do the following:
+<code bash>
+sudo cp /etc/ldap/tls/ca.crt /usr/local/share/ca-certificates/radiusdesk-ca.crt
+sudo update-ca-certificates
+#This is the output on our system
+Updating certificates in /etc/ssl/certs...
+rehash: warning: skipping ca-certificates.crt,it does not contain exactly one certificate or CRL
+added, 0 removed; done.
+Running hooks in /etc/ca-certificates/update.d...
+Processing triggers for ca-certificates-java (20240118) ...
+Adding debian:radiusdesk-ca.pem
+done.
+done.
+#Now we can just use plain ldapsearch
+ldapsearch -H ldaps://ldap.radiusdesk.com -x -D "cn=admin,dc=radiusdesk,dc=com" -w testing123 -b dc=radiusdesk,dc=com
+</code>
+</WRAP>
+==== What does update-ca-certificates do? ====
+I like to know how things work. If you also like to know how things work the following insert is for you :-)
+  * The primary master CA file that is updated and can be used on Ubuntu is  **/etc/ssl/certs/ca-certificates.crt**
+  * This command rebuilds the system's trusted certificate store by consolidating certificates from a few key locations:
+    * **System Certificates:** The command reads the configuration file **/etc/ca-certificates.conf** to determine which certificates from **/usr/share/ca-certificates/** should be trusted.
+    * **Local Certificates:** It automatically trusts all .crt files found in /usr/local/share/ca-certificates/. This is the place where we add our internal CA certificate.
+  * **Output:** It then generates the single, concatenated bundle file at **/etc/ssl/certs/ca-certificates.crt**. This file is the master list used by many applications (like OpenSSL) to verify SSL/TLS connections.
+==== Update FreeRADIUS for ldaps:// ====
+  * Do the following steps.
+<code bash>
+sudo su
+#Copy the OpenLDAP's CA to FreeRADIUS
+cp /etc/ldap/tls/ca /etc/freeradius/3.0/certs/ca.crt
+</code>
+  * Edit **/etc/freeradius/3.0/mods-enabled/ldap**
+<code bash>
+#Look for these items...
+#server = 'localhost'
+#---This has to match the cert's  ubjectAltName (SAN)---
+server = 'ldap.radiusdesk.com'
+#       server = 'ldap.rrdns.example.org'
+#       server = 'ldap.rrdns.example.org'
+#  Port to connect on, defaults to 389, will be ignored for LDAP URIs.
+##port = 389
+#--We specify the ldaps port--
+port = 636
+#--- Then loop for the tls section
+tls {
+        # Set this to 'yes' to use TLS encrypted connections
+        # to the LDAP database by using the StartTLS extended
+        # operation.
+        #
+        # The StartTLS operation is supposed to be
+        # used with normal ldap connections instead of
+        # using ldaps (port 636) connections
+        #--- Disable start_tls since we are forcing ssl/tls ---
+        #start_tls = yes
+#               ca_file = ${certdir}/cacert.pem
+       #--- The CA file from OpenLDAP--
+        ca_file = /etc/freeradius/3.0/certs/ca.crt
+#               ca_path = ${certdir}
+#               certificate_file = /path/to/radius.crt
+#               private_key_file = /path/to/radius.key
+#               random_file = /dev/urandom
+        #  Certificate Verification requirements.  Can be:
+        #    'never' (do not even bother trying)
+        #    'allow' (try, but don't fail if the certificate
+        #               cannot be verified)
+        #    'demand' (fail if the certificate does not verify)
+        #    'hard'  (similar to 'demand' but fails if TLS
+        #             cannot negotiate)
+        #
+        #  The default is libldap's default, which varies based
+        #  on the contents of ldap.conf.
+        #---Enforce FreeRADIUS to check the validity of the certificate ---
+        require_cert    = 'demand'
+        #
+        #  Check the CRL, as with the EAP module.
+        #
+</code>
+  * After you made these changes, restart FreeRADIUS in debug mode and to a test authentication to confirm that it is now using ldaps (port 636)
+  * See the results from out setup below:
+<code bash>
+rlm_ldap (ldap): Reserved connection (3)
+(3) ldap: EXPAND (uid=%{%{Stripped-User-Name}:-%{User-Name}})
+(3) ldap:    --> (uid=testuser)
+(3) ldap: Performing search in "ou=people,dc=radiusdesk,dc=com" with filter "(uid=testuser)", scope "sub"
+(3) ldap: Waiting for search result...
+(3) ldap: User object found at DN "uid=testuser,ou=people,dc=radiusdesk,dc=com"
+(3) ldap: Processing user attributes
+(3) ldap: control:Password-With-Header += 'mysecretpassword'
+rlm_ldap (ldap): Released connection (3)
+Need more connections to reach 10 spares
+rlm_ldap (ldap): Opening additional connection (7), 1 of 25 pending slots used
+rlm_ldap (ldap): Connecting to ldap://ldap.radiusdesk.com:636
+rlm_ldap (ldap): Waiting for bind result...
+rlm_ldap (ldap): Bind successful
+</code>
-==== Install OpenLDAP ====