我正在为Linux机器配置LDAP用户登录功能，目前通过su命令可以切换到LDAP列表里的任意用户，同时也会自动创建对应的用户目录，所以我觉得nsswitch.conf应该没有问题。

但是当我尝试通过SSH登录同一台Linux机器时，总是收到以下错误：

Permission denied, please try again.

我确认凭据是正确的，因为用su命令完全可以正常使用。我怀疑问题出在/etc/ldap.conf文件上，有没有人能帮我排查一下？

/etc/ldap.conf 配置 #

###DEBCONF###

##
## Configuration of this file will be managed by debconf as long as the
## first line of the file says '###DEBCONF###'
##
## You should use dpkg-reconfigure to configure this file via debconf
##
#
# @(#)$Id: ldap.conf,v 1.38 2006/05/15 08:13:31 lukeh Exp $
#
# This is the configuration file for the LDAP nameservice
# switch library and the LDAP PAM module.
#
# PADL Software
# http://www.padl.com
#
# 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=dev,dc=asavie,dc=net
# Another way to specify your LDAP server is to provide an
uri ldap://172.17.4.90:389
# 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=admin,dc=dev,dc=asavie,dc=net
# The credentials to bind with.
# Optional: default is no credential.
bindpw **********
# 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=manager,dc=padl,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

PAM 配置文件 #

common-account #

account [success=2 new_authtok_reqd=done default=ignore]        pam_unix.so
account [success=1 default=ignore]      pam_ldap.so
account requisite                       pam_deny.so
account required                        pam_permit.so

common-auth #

auth sufficient pam_ldap.so
auth    [success=2 default=ignore]      pam_unix.so nullok_secure
auth    [success=1 default=ignore]      pam_ldap.so use_first_pass
auth    requisite                       pam_deny.so
auth    required                        pam_permit.so
auth    optional                        pam_cap.so

common-password #

password        [success=2 default=ignore]      pam_unix.so obscure sha512
password        [success=1 user_unknown=ignore default=die]     pam_ldap.so try_first_pass
password        requisite                       pam_deny.so
password        required                        pam_permit.so

/etc/ssh/sshd_config 配置 #

PubkeyAuthentication yes
# Expect .ssh/authorized_keys2 to be disregarded by default in future.
#AuthorizedKeysFile     .ssh/authorized_keys .ssh/authorized_keys2
#AuthorizedPrincipalsFile none
#AuthorizedKeysCommand none
#AuthorizedKeysCommandUser nobody

# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
#HostbasedAuthentication no
# Change to yes if you don't trust ~/.ssh/known_hosts for
# HostbasedAuthentication
#IgnoreUserKnownHosts no
# Don't read the user's ~/.rhosts and ~/.shosts files
#IgnoreRhosts yes

# To disable tunneled clear text passwords, change to no here!
#PasswordAuthentication yes
#PermitEmptyPasswords no

# Change to yes to enable challenge-response passwords (beware issues with
# some PAM modules and threads)
ChallengeResponseAuthentication no

# Kerberos options
#KerberosAuthentication no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes
#KerberosGetAFSToken no

# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes
#GSSAPIStrictAcceptorCheck yes
#GSSAPIKeyExchange no

# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
# be allowed through the ChallengeResponseAuthentication and
# PasswordAuthentication.  Depending on your PAM configuration,
# PAM authentication via ChallengeResponseAuthentication may bypass
# the setting of "PermitRootLogin without-password".
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and ChallengeResponseAuthentication to 'no'.
UsePAM yes

#AllowAgentForwarding yes
#AllowTcpForwarding yes
#GatewayPorts no
X11Forwarding yes
AllowUsers sreuser ansibledeploy sbhutani ptest
#X11DisplayOffset 10
#X11UseLocalhost yes
#PermitTTY yes
PrintMotd yes
#PrintLastLog yes
#TCPKeepAlive yes
#PermitUserEnvironment no
#Compression delayed
#ClientAliveInterval 0
#ClientAliveCountMax 3
#UseDNS no
#PidFile /var/run/sshd.pid
#MaxStartups 10:30:100
#PermitTunnel no
#ChrootDirectory none
#VersionAddendum none

# no default banner path
#Banner none

# Allow client to pass locale environment variables
AcceptEnv LANG LC_*

# override default of no subsystems
Subsystem sftp  /usr/lib/openssh/sftp-server

# Example of overriding settings on a per-user basis
#Match User anoncvs
#       X11Forwarding no
#       AllowTcpForwarding no
#       PermitTTY no
#       ForceCommand cvs server
PasswordAuthentication yes

备注：内容来源于stack exchange，提问作者mikey1996