[RHCE] LDAP User Authentication

1.LDAP User Authentication

---

* Configure ldap client for authentication.
==========================================
1)/etc/nsswitch.conf
 ==
  passwd : files ==> files sss (ssl ldap)
  shadow : ...

2)Search /etc/passwd (First, if no user, move to ldap)
    
3)Search LDAP


* Check pass mapper
=========================
# getent passwd ldapuser1

==> First, check file and ldap because passwd means it should find /etc/nsswitch.conf file.
    So search file and ldap step by step.
    It can not find ldapuser1 in file but find in ldap.

*Auto mount
==============================
In order to reduce network load,
  ==> Auto mount
     1) NFS Clinet Feature
     2) If need, mount it automatically but the opposite, unmount it automatically.
     3) how to

      #/etc/auto.master
        mnt_point    map_file (resource : /etc)
       /dir1          map1

      #/etc/map1
       /dir2        inst:/var/nfs
      # service autofs restart
      # cd /dir1/dir2   

       =>(Note) inactive of the mount during 10 mins, it will be unmounted.

Regular Expression, 
   ==>  #/etc/map1
        *        inst:/var/&   (& means the value right before used value.)
                               (Here==>*)


*Input Method (한글 사용하기)
==========================
#yum groupinstall 'Input Method'
==> inut method tab => Add Korean 
==> Advanced tab => Share the same input method among all applications 클릭



*SSH key로 로그인하기
===================

             Client ---------> Server
 ssh-key-gen  pub/pri 
 ssh-copy-id  copy pub--------> pub
 
Steps)
1. ssh-key-gen
2. ssh-copy-id server1 (ssh-copy-id -i /home/jooho/.ssh/test_rsa.pub root@desktop1)


(/etc/ssh/sshd_config 설정파일)
만약 private 키가 노출되었을 경우를 대비해서 private key자체에 암호를 걸수 있다.
그런데 이러면 매번 암호를 넣어야 하는 불편함이 있다.
ssh-add/ssh-agent를 통해서 캐쉬에 담아두고 컴퓨터가 켜져 있는 동안에는 매번 암호를 넣지 않게 만들수 있다.
Steps)

[root@desktop1 ~]# ssh-agent  SSH_AUTH_SOCK=/tmp/ssh-sWZYe18375/agent.18375; export SSH_AUTH_SOCK; SSH_AGENT_PID=18376; export SSH_AGENT_PID; echo Agent pid 18376; [root@desktop1 ~]# ssh-add Enter passphrase for /root/.ssh/id_rsa:  Identity added: /root/.ssh/id_rsa (/root/.ssh/id_rsa) [root@desktop1 ~]# ssh server1 Last login: Mon Apr 14 11:46:43 2014 from desktop1.example.com