Security Software

LDAP Gurus,

I want to sent an email notification before user's password is expired, so I need get the value of attribute "passwordexpirationtime" for all the users.
while I tried a lot of ways, but I can not see and get the value.
e.g command and output of 1 user as follow

ldapsearch -p 370 -h ldapserver.abc.com -b 'ou=People,dc=abc,dc=com' objectclass=*
....
dn: uid=user1,ou=People, dc=abc,dc=com
objectClass: top
objectClass: person
objectClass: organizationalPerson
objectClass: inetorgperson
objectClass: posixAccount
objectClass: shadowaccount
givenName: John
sn: Paul
description: John Paul
loginShell: /bin/bash
gidNumber: 9042
uidNumber: 9042
uid: user1
cn: John Paul
gecos: John Paul
homeDirectory: /export/home/user1
....

Question:
which ldap command and options can be used to get the value of attribute "passwordexpirationtime" for all the users.

Environment:
Sun Directory Server 5.2_Patch_4


Thanks you in advance.