OpenLDAP : LDAP over SSL/TLS2025/04/22

	Configure LDAP over SSL/TLS to use secure encrypted connection.
[1]	On this example, create and use self-signed certificates like here.
[2]	Configure LDAP Server.

root@dlp:~#

cp /etc/ssl/private/server.key \
/etc/ssl/private/server.crt \
/etc/ldap/sasl2/

root@dlp:~#

chown openldap:openldap /etc/ldap/sasl2/server.key \
/etc/ldap/sasl2/server.crt

root@dlp:~#

vi mod_ssl.ldif

# create new

dn: cn=config
changetype: modify
replace: olcTLSCertificateFile
olcTLSCertificateFile: /etc/ldap/sasl2/server.crt
-
replace: olcTLSCertificateKeyFile
olcTLSCertificateKeyFile: /etc/ldap/sasl2/server.key

root@dlp:~#

ldapmodify -Y EXTERNAL -H ldapi:/// -f mod_ssl.ldif

SASL/EXTERNAL authentication started
SASL username: gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth
SASL SSF: 0
modifying entry "cn=config"

root@dlp:~#

systemctl restart slapd

[3]	Configure LDAP Client. If you'd like to make sure the connection between LDAP server and client is encrypted, use tcpdump or other network capture softwares on LDAP server.

root@node01:~#

vi /etc/nslcd.conf

# line 29 : add

ssl start_tls
tls_reqcert allow

root@node01:~#

systemctl restart nslcd

root@node01:~#

exit

node01 login: plucky     # LDAP user
Password:
Welcome to Ubuntu 25.04 (GNU/Linux 6.14.0-15-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/pro

.....
.....

plucky@node01:~$      # logined

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