Thanks for your reply...
Yeah... I think i configured correctly in my client. I can use ldapsearch with commands:
./ldapsearch -xLL -b dc=abc,dc=com -H ldaps://ftp.abc.com '(uid=khanhnq)' -d -1
.......
02a0: 63 1c c8 a4 32 02 b0 8c bb 17 79 54 29 9d d1 61 c...2.....yT)..a
02b0: 05 82 04 60 53 30 d6 27 26 d4 e3 21 51 4c 95 d2 ...`S0.'...u..,.)..... 0310: 07 7c d6 34 f5 8c 0c 14 13 6a dd aa 62 92 63 58 .|.4.....j..b.cX 0320: a6 56 12 5f f1 1c 20 ad 59 8f eb 6a 9a 3c cc 7e .V._.. .Y..j.