Ldap – getent password not returning LDAP users

I am following this tutorial https://mcwhirter.com.au/craige/blog/2005/Making-a-Debian-or-Ubuntu-Machine-an-LDAP-Authentication-Client/ but after the first step:

apt-get install libpam-ldap libnss-ldap

it already fails:

you should be able to run commands such as "getent passwd"

but the LDAP users do not appear. I don't know what to do from there. I spent the whole day trying to understand what is wrong and double-checking everything but I can't find out. How can I troubleshoot my configuration?

I followed the Troubleshooting section in this other tutorial:

• Check your /var/log/messages file: empty on the LDAP server and non-existing on the PC

• Testing Basic Connectivity: OK:

  telnet 123.123.123.123 389 # on PC
  
     Trying 123.123.123.123...
     Connected to 123.123.123.123.
     Escape character is '^]'.
  

• Testing Using ldapsearch

I performed different random checks whose relevance I am not sure of. Assuming 123.123.123.123 is the IP of the LDAP server sub.domain.com its full domain name:

ldapsearch -x -b 'dc=sub,dc=domain,dc=com' '(objectclass=*)' ### ON SERVER

    ldap_bind: Inappropriate authentication (48)
    additional info: anonymous bind disallowed

and on the PC:

ldapsearch -x -b 'dc=sub,dc=domain,dc=com' '(objectclass=*)' ### ON CLIENT

    ldap_sasl_bind(SIMPLE): Can't contact LDAP server (-1)

@user5870571's answer explains that I need to create a LDAP user with the rights to list the LDAP users. However I don't understand how this articulates with the tutorial I have followed and I don't know how to correct this.

On the server's side:

slaptest

returns

bdb_monitor_db_open: monitoring disabled; configure monitor database to enable

config file testing succeeded

I'd be very happy to share outputs of specific commands or file contents, on your request.

cat /etc/ldap.conf

# Your LDAP server. Must be resolvable without using LDAP.
# Multiple hosts may be specified, each separated by a 
# space. How long nss_ldap takes to failover depends on
# whether your LDAP client library supports configurable
# network or connect timeouts (see bind_timelimit).
#host 127.0.0.1

# The distinguished name of the search base.
base dc=sub,dc=domain,dc=com

# Another way to specify your LDAP server is to provide an
uri ldap://123.123.123.123
# Unix Domain Sockets to connect to a local LDAP Server.
#uri ldap://127.0.0.1/
#uri ldaps://127.0.0.1/   
#uri ldapi://%2fvar%2frun%2fldapi_sock/
# Note: %2f encodes the '/' used as directory separator

# The LDAP version to use (defaults to 3
# if supported by client library)
ldap_version 3

# The distinguished name to bind to the server with.
# Optional: default is to bind anonymously.
#binddn cn=proxyuser,dc=padl,dc=com

# The credentials to bind with. 
# Optional: default is no credential.
#bindpw secret

# The distinguished name to bind to the server with
# if the effective user ID is root. Password is
# stored in /etc/ldap.secret (mode 600)
rootbinddn cn=admin,dc=sub,dc=domain,dc=com

# The port.
# Optional: default is 389.
#port 389

# The search scope.
#scope sub
#scope one
#scope base

# Search timelimit
#timelimit 30

# Bind/connect timelimit
#bind_timelimit 30

# Reconnect policy: hard (default) will retry connecting to
# the software with exponential backoff, soft will fail
# immediately.
#bind_policy hard

# Idle timelimit; client will close connections
# (nss_ldap only) if the server has not been contacted
# for the number of seconds specified below.
#idle_timelimit 3600

# Filter to AND with uid=%s
#pam_filter objectclass=account

# The user ID attribute (defaults to uid)
#pam_login_attribute uid

# Search the root DSE for the password policy (works
# with Netscape Directory Server)
#pam_lookup_policy yes

# Check the 'host' attribute for access control
# Default is no; if set to yes, and user has no
# value for the host attribute, and pam_ldap is
# configured for account management (authorization)
# then the user will not be allowed to login.
#pam_check_host_attr yes

# Check the 'authorizedService' attribute for access
# control
# Default is no; if set to yes, and the user has no
# value for the authorizedService attribute, and
# pam_ldap is configured for account management
# (authorization) then the user will not be allowed
# to login.
#pam_check_service_attr yes

# Group to enforce membership of
#pam_groupdn cn=PAM,ou=Groups,dc=padl,dc=com

# Group member attribute
#pam_member_attribute uniquemember

# Specify a minium or maximum UID number allowed
#pam_min_uid 0
#pam_max_uid 0

# Template login attribute, default template user
# (can be overriden by value of former attribute
# in user's entry)
#pam_login_attribute userPrincipalName
#pam_template_login_attribute uid
#pam_template_login nobody

# HEADS UP: the pam_crypt, pam_nds_passwd,
# and pam_ad_passwd options are no
# longer supported.
#
# Do not hash the password at all; presume
# the directory server will do it, if
# necessary. This is the default.
pam_password md5

# Hash password locally; required for University of
# Michigan LDAP server, and works with Netscape
# Directory Server if you're using the UNIX-Crypt
# hash mechanism and not using the NT Synchronization
# service. 
#pam_password crypt

# Remove old password first, then update in
# cleartext. Necessary for use with Novell
# Directory Services (NDS)
#pam_password clear_remove_old
#pam_password nds

# RACF is an alias for the above. For use with
# IBM RACF
#pam_password racf

# Update Active Directory password, by
# creating Unicode password and updating
# unicodePwd attribute.
#pam_password ad

# Use the OpenLDAP password change
# extended operation to update the password.
#pam_password exop

# Redirect users to a URL or somesuch on password
# changes.
#pam_password_prohibit_message Please visit http://internal to change your password.

# RFC2307bis naming contexts
# Syntax:
# nss_base_XXX      base?scope?filter
# where scope is {base,one,sub}
# and filter is a filter to be &'d with the
# default filter.
# You can omit the suffix eg:
# nss_base_passwd   ou=People,
# to append the default base DN but this
# may incur a small performance impact.
#nss_base_passwd    ou=People,dc=padl,dc=com?one
#nss_base_shadow    ou=People,dc=padl,dc=com?one
#nss_base_group     ou=Group,dc=padl,dc=com?one
#nss_base_hosts     ou=Hosts,dc=padl,dc=com?one
#nss_base_services  ou=Services,dc=padl,dc=com?one
#nss_base_networks  ou=Networks,dc=padl,dc=com?one
#nss_base_protocols ou=Protocols,dc=padl,dc=com?one
#nss_base_rpc       ou=Rpc,dc=padl,dc=com?one
#nss_base_ethers    ou=Ethers,dc=padl,dc=com?one
#nss_base_netmasks  ou=Networks,dc=padl,dc=com?ne
#nss_base_bootparams    ou=Ethers,dc=padl,dc=com?one
#nss_base_aliases   ou=Aliases,dc=padl,dc=com?one
#nss_base_netgroup  ou=Netgroup,dc=padl,dc=com?one

# attribute/objectclass mapping
# Syntax:
#nss_map_attribute  rfc2307attribute    mapped_attribute
#nss_map_objectclass    rfc2307objectclass  mapped_objectclass

# configure --enable-nds is no longer supported.
# NDS mappings
#nss_map_attribute uniqueMember member

# Services for UNIX 3.5 mappings
#nss_map_objectclass posixAccount User
#nss_map_objectclass shadowAccount User
#nss_map_attribute uid msSFU30Name
#nss_map_attribute uniqueMember msSFU30PosixMember
#nss_map_attribute userPassword msSFU30Password
#nss_map_attribute homeDirectory msSFU30HomeDirectory
#nss_map_attribute homeDirectory msSFUHomeDirectory
#nss_map_objectclass posixGroup Group
#pam_login_attribute msSFU30Name
#pam_filter objectclass=User
#pam_password ad

# configure --enable-mssfu-schema is no longer supported.
# Services for UNIX 2.0 mappings
#nss_map_objectclass posixAccount User
#nss_map_objectclass shadowAccount user
#nss_map_attribute uid msSFUName
#nss_map_attribute uniqueMember posixMember
#nss_map_attribute userPassword msSFUPassword
#nss_map_attribute homeDirectory msSFUHomeDirectory
#nss_map_attribute shadowLastChange pwdLastSet
#nss_map_objectclass posixGroup Group
#nss_map_attribute cn msSFUName
#pam_login_attribute msSFUName
#pam_filter objectclass=User
#pam_password ad

# RFC 2307 (AD) mappings
#nss_map_objectclass posixAccount user
#nss_map_objectclass shadowAccount user
#nss_map_attribute uid sAMAccountName
#nss_map_attribute homeDirectory unixHomeDirectory
#nss_map_attribute shadowLastChange pwdLastSet
#nss_map_objectclass posixGroup group
#nss_map_attribute uniqueMember member
#pam_login_attribute sAMAccountName
#pam_filter objectclass=User
#pam_password ad

# configure --enable-authpassword is no longer supported
# AuthPassword mappings
#nss_map_attribute userPassword authPassword

# AIX SecureWay mappings
#nss_map_objectclass posixAccount aixAccount
#nss_base_passwd ou=aixaccount,?one
#nss_map_attribute uid userName
#nss_map_attribute gidNumber gid
#nss_map_attribute uidNumber uid
#nss_map_attribute userPassword passwordChar
#nss_map_objectclass posixGroup aixAccessGroup
#nss_base_group ou=aixgroup,?one
#nss_map_attribute cn groupName
#nss_map_attribute uniqueMember member
#pam_login_attribute userName
#pam_filter objectclass=aixAccount
#pam_password clear

# Netscape SDK LDAPS
#ssl on

# Netscape SDK SSL options
#sslpath /etc/ssl/certs

# OpenLDAP SSL mechanism
# start_tls mechanism uses the normal LDAP port, LDAPS typically 636
#ssl start_tls
#ssl on

# OpenLDAP SSL options
# Require and verify server certificate (yes/no)
# Default is to use libldap's default behavior, which can be configured in
# /etc/openldap/ldap.conf using the TLS_REQCERT setting.  The default for
# OpenLDAP 2.0 and earlier is "no", for 2.1 and later is "yes".
#tls_checkpeer yes

# CA certificates for server certificate verification
# At least one of these are required if tls_checkpeer is "yes"
#tls_cacertfile /etc/ssl/ca.cert
#tls_cacertdir /etc/ssl/certs

# Seed the PRNG if /dev/urandom is not provided
#tls_randfile /var/run/egd-pool

# SSL cipher suite
# See man ciphers for syntax
#tls_ciphers TLSv1

# Client certificate and key
# Use these, if your server requires client authentication.
#tls_cert
#tls_key

# Disable SASL security layers. This is needed for AD.
#sasl_secprops maxssf=0

# Override the default Kerberos ticket cache location.
#krb5_ccname FILE:/etc/.ldapcache

# SASL mechanism for PAM authentication - use is experimental
# at present and does not support password policy control
#pam_sasl_mech DIGEST-MD5