openldap
Try to follow the instructions very precisely because LDAP syntax is sometimes cumbersome (case sensitive, space, etc) and prone to errors (dn/dc/cn).
Let’s assume that we use the example.com domain and the instructor.example.com hostname.
Install the following packages:
# yum install -y openldap openldap-clients openldap-servers migrationtools
Generate a LDAP password from a secret key (here redhat):
# slappasswd -s redhat -n > /etc/openldap/passwd
Generate a X509 certificate valid for 365 days:
# openssl req -new -x509 -nodes -out /etc/openldap/certs/cert.pem -keyout /etc/openldap/certs/priv.pem -days 365Generating a 2048 bit RSA private key .....+++ ..............+++ writing new private key to '/etc/openldap/certs/priv.pem' ----- You are about to be asked to enter information that will be incorporated into your certificate request. What you are about to enter is what is called a Distinguished Name or a DN. There are quite a few fields but you can leave some blank For some fields there will be a default value, If you enter '.', the field will be left blank. ----- Country Name (2 letter code) [XX]: State or Province Name (full name) []: Locality Name (eg, city) [Default City]: Organization Name (eg, company) [Default Company Ltd]: Organizational Unit Name (eg, section) []: Common Name (eg, your name or your server's hostname) []:instructor.example.comEmail Address []:
Secure the content of the /etc/openldap/certs directory:
# cd /etc/openldap/certs# chown ldap:ldap *# chmod 600 priv.pem
Prepare the LDAP database:
# cp /usr/share/openldap-servers/DB_CONFIG.example /var/lib/ldap/DB_CONFIG
Generate database files (don’t worry about error messages!):
# slaptest53d61aab hdb_db_open: database "dc=my-domain,dc=com": db_open(/var/lib/ldap/id2entry.bdb) failed: No such file or directory (2). 53d61aab backend_startup_one (type=hdb, suffix="dc=my-domain,dc=com"): bi_db_open failed! (2) slap_startup failed (test would succeed using the -u switch)
Change LDAP database ownership:
# chown ldap:ldap /var/lib/ldap/*
Activate the slapd service at boot:
# systemctl enable slapd
Start the slapd service:
# systemctl start slapd
Check the LDAP activity:
# netstat -lt | grep ldaptcp 0 0 0.0.0.0:ldap 0.0.0.0:* LISTEN tcp6 0 0 [::]:ldap [::]:* LISTEN
To start the configuration of the LDAP server, add the cosine & nis LDAP schemas:
# cd /etc/openldap/schema# ldapadd -Y EXTERNAL -H ldapi:/// -D "cn=config" -f cosine.ldifSASL/EXTERNAL authentication started SASL username: gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth SASL SSF: 0 adding new entry "cn=cosine,cn=schema,cn=config" # ldapadd -Y EXTERNAL -H ldapi:/// -D "cn=config" -f nis.ldifSASL/EXTERNAL authentication started SASL username: gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth SASL SSF: 0 adding new entry "cn=nis,cn=schema,cn=config"
Then, create the /etc/openldap/changes.ldif file and paste the following lines (replace password with the previously created password):
dn: olcDatabase={2}hdb,cn=config
changetype: modify
replace: olcSuffix
olcSuffix: dc=example,dc=com
dn: olcDatabase={2}hdb,cn=config
changetype: modify
replace: olcRootDN
olcRootDN: cn=Manager,dc=example,dc=com
dn: olcDatabase={2}hdb,cn=config
changetype: modify
replace: olcRootPW
olcRootPW: passwd # previously generated password
dn: cn=config
changetype: modify
replace: olcTLSCertificateFile
olcTLSCertificateFile: /etc/openldap/certs/cert.pem
dn: cn=config
changetype: modify
replace: olcTLSCertificateKeyFile
olcTLSCertificateKeyFile: /etc/openldap/certs/priv.pem
dn: cn=config
changetype: modify
replace: olcLogLevel
olcLogLevel: -1
dn: olcDatabase={1}monitor,cn=config
changetype: modify
replace: olcAccess
olcAccess: {0}to * by dn.base="gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth" read by dn.base="cn=Manager,dc=example,dc=com" read by * none
Send the new configuration to the slapd server:
# ldapmodify -Y EXTERNAL -H ldapi:/// -f /etc/openldap/changes.ldifSASL/EXTERNAL authentication started
SASL username: gidNumber=0+uidNumber=0,cn=peercred,cn=external,cn=auth
SASL SSF: 0
modifying entry "olcDatabase={2}hdb,cn=config"
modifying entry "olcDatabase={2}hdb,cn=config"
modifying entry "olcDatabase={2}hdb,cn=config"
modifying entry "cn=config"
modifying entry "cn=config"
modifying entry "cn=config"
modifying entry "olcDatabase={1}monitor,cn=config"
Create the /etc/openldap/base.ldif file and paste the following lines:
dn: dc=example,dc=com dc: example objectClass: top objectClass: domain dn: ou=People,dc=example,dc=com ou: People objectClass: top objectClass: organizationalUnit dn: ou=Group,dc=example,dc=com ou: Group objectClass: top objectClass: organizationalUnit
Build the structure of the directory service:
# ldapadd -x -w redhat -D cn=Manager,dc=example,dc=com -f base.ldifadding new entry "dc=example,dc=com" adding new entry "ou=People,dc=example,dc=com" adding new entry "ou=Group,dc=example,dc=com"
Create two users for testing:
# mkdir /home/guests# useradd -d /home/guests/ldapuser01 ldapuser01# passwd ldapuser01Changing password for user ldapuser01. New password:user01ldapRetype new password:user01ldappasswd: all authentication tokens updated successfully. # useradd -d /home/guests/ldapuser02 ldapuser02# passwd ldapuser02Changing password for user ldapuser02. New password:user02ldapRetype new password:user02ldappasswd: all authentication tokens updated successfully.
Go to the directory for the migration of the user accounts:
# cd /usr/share/migrationtools
Edit the migrate_common.ph file and replace in the following lines:
$DEFAULT_MAIL_DOMAIN = "example.com"; $DEFAULT_BASE = "dc=example,dc=com";
Create the current users in the directory service:
# grep ":10[0-9][0-9]" /etc/passwd > passwd# ./migrate_passwd.pl passwd users.ldif# ldapadd -x -w redhat -D cn=Manager,dc=example,dc=com -f users.ldifadding new entry "uid=ldapuser01,ou=People,dc=example,dc=com" adding new entry "uid=ldapuser02,ou=People,dc=example,dc=com" # grep ":10[0-9][0-9]" /etc/group > group# ./migrate_group.pl group groups.ldif# ldapadd -x -w redhat -D cn=Manager,dc=example,dc=com -f groups.ldifadding new entry "cn=ldapuser01,ou=Group,dc=example,dc=com" adding new entry "cn=ldapuser02,ou=Group,dc=example,dc=com"
Test the configuration with the user called ldapuser01:
# ldapsearch -x cn=ldapuser01 -b dc=example,dc=com
Add a new service to the firewall (ldap: port tcp 389):
# firewall-cmd --permanent --add-service=ldap
Reload the firewall configuration:
# firewall-cmd --reload
Edit the /etc/rsyslog.conf file and add the following line:
local4.* /var/log/ldap.log
Restart the rsyslog service:http://www.certdepot.net
# systemctl restart rsyslog