我已经进行了 LDAP 身份验证配置，并尝试在 Ubuntu 14.04 TLS 上对 LDAP 服务器进行身份验证。这是文件 nsswitch.conf ：
# /etc/nsswitch.conf
#
# Example configuration of GNU Name Service Switch functionality.
# If you have the `glibc-doc-reference' and `info' packages installed, try:
# `info libc "Name Service Switch"' for information about this file.
# pre_auth-client-config # passwd: compat ldap
passwd: files ldap
# pre_auth-client-config # group: compat ldap
group: files ldap
# pre_auth-client-config # shadow: compat ldap
shadow: files ldap
hosts: files mdns4_minimal [NOTFOUND=return] dns
networks: files
protocols: …